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Sample records for multidimensional liquid chromatography

  1. Column Liquid Chromatography.

    Science.gov (United States)

    Majors, Ronald E.; And Others

    1984-01-01

    Reviews literature covering developments of column liquid chromatography during 1982-83. Areas considered include: books and reviews; general theory; columns; instrumentation; detectors; automation and data handling; multidimensional chromatographic and column switching techniques; liquid-solid chromatography; normal bonded-phase, reversed-phase,…

  2. Comprehensive lipidomic analysis of human plasma using multidimensional liquid- and gas-phase separations: Two-dimensional liquid chromatography-mass spectrometry vs. liquid chromatography-trapped-ion-mobility-mass spectrometry.

    Science.gov (United States)

    Baglai, Anna; Gargano, Andrea F G; Jordens, Jan; Mengerink, Ynze; Honing, Maarten; van der Wal, Sjoerd; Schoenmakers, Peter J

    2017-12-29

    Recent advancements in separation science have resulted in the commercialization of multidimensional separation systems that provide higher peak capacities and, hence, enable a more-detailed characterization of complex mixtures. In particular, two powerful analytical tools are increasingly used by analytical scientists, namely online comprehensive two-dimensional liquid chromatography (LC×LC, having a second-dimension separation in the liquid phase) and liquid chromatography-ion mobility-spectrometry (LC-IMS, second dimension separation in the gas phase). The goal of the current study was a general assessment of the liquid-chromatography-trapped-ion-mobility-mass spectrometry (LC-TIMS-MS) and comprehensive two-dimensional liquid chromatography-mass spectrometry (LC×LC-MS) platforms for untargeted lipid mapping in human plasma. For the first time trapped-ion-mobility spectrometry (TIMS) was employed for the separation of the major lipid classes and ion-mobility-derived collision-cross-section values were determined for a number of lipid standards. The general effects of a number of influencing parameters have been inspected and possible directions for improvements are discussed. We aimed to provide a general indication and practical guidelines for the analyst to choose an efficient multidimensional separation platform according to the particular requirements of the application. Analysis time, orthogonality, peak capacity, and an indicative measure for the resolving power are discussed as main characteristics for multidimensional separation systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. LC-IMS-MS Feature Finder: detecting multidimensional liquid chromatography, ion mobility and mass spectrometry features in complex datasets.

    Science.gov (United States)

    Crowell, Kevin L; Slysz, Gordon W; Baker, Erin S; LaMarche, Brian L; Monroe, Matthew E; Ibrahim, Yehia M; Payne, Samuel H; Anderson, Gordon A; Smith, Richard D

    2013-11-01

    The addition of ion mobility spectrometry to liquid chromatography-mass spectrometry experiments requires new, or updated, software tools to facilitate data processing. We introduce a command line software application LC-IMS-MS Feature Finder that searches for molecular ion signatures in multidimensional liquid chromatography-ion mobility spectrometry-mass spectrometry (LC-IMS-MS) data by clustering deisotoped peaks with similar monoisotopic mass, charge state, LC elution time and ion mobility drift time values. The software application includes an algorithm for detecting and quantifying co-eluting chemical species, including species that exist in multiple conformations that may have been separated in the IMS dimension. LC-IMS-MS Feature Finder is available as a command-line tool for download at http://omics.pnl.gov/software/LC-IMS-MS_Feature_Finder.php. The Microsoft.NET Framework 4.0 is required to run the software. All other dependencies are included with the software package. Usage of this software is limited to non-profit research to use (see README). rds@pnnl.gov. Supplementary data are available at Bioinformatics online.

  4. Characterization of the pigment fraction in sweet bell peppers (Capsicum annuum L.) harvested at green and overripe yellow and red stages by offline multidimensional convergence chromatography/liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Bonaccorsi, Ivana; Cacciola, Francesco; Utczas, Margita; Inferrera, Veronica; Giuffrida, Daniele; Donato, Paola; Dugo, Paola; Mondello, Luigi

    2016-09-01

    Offline multidimensional supercritical fluid chromatography combined with reversed-phase liquid chromatography was employed for the carotenoid and chlorophyll characterization in different sweet bell peppers (Capsicum annuum L.) for the first time. The first dimension consisted of an Acquity HSS C18 SB (100 × 3 mm id, 1.8 μm particles) column operated with a supercritical mobile phase in an ultra-performance convergence chromatography system, whereas the second dimension was performed in reversed-phase mode with a C30 (250 × 4.6 mm id, 3.0 μm particles) stationary phase combined with photodiode array and mass spectrometry detection. This approach allowed the determination of 115 different compounds belonging to chlorophylls, free xanthophylls, free carotenes, xanthophyll monoesters, and xanthophyll diesters, and proved to be a significant improvement in the pigments determination compared to the conventional one-dimensional liquid chromatography approach so far applied to the carotenoid analysis in the studied species. Moreover, the present study also aimed to investigate and to compare the carotenoid stability and composition in overripe yellow and red bell peppers collected directly from the plant, thus also evaluating whether biochemical changes are linked to carotenoid degradation in the nonclimacteric investigated fruits, for the first time. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Liquid Chromatography in 1982.

    Science.gov (United States)

    Freeman, David H.

    1982-01-01

    Reviews trends in liquid chromatography including apparatus, factors affecting efficient separation of a mixture (peak sharpness and speed), simplified problem-solving, adsorption, bonded phase chromatography, ion selectivity, and size exclusion. The current trend is to control chemical selectivity by the liquid phase. (Author/JN)

  6. Comprehensive lipidomic analysis of human plasma using multidimensional liquid- and gas-phase separations: Two-dimensional liquid chromatography-mass spectrometry vs. liquid chromatography-trapped-ion-mobility-mass spectrometry

    NARCIS (Netherlands)

    Baglai, A.; Gargano, A.F.G.; Jordens, J.; Mengerink, Y.; Honing, M.; van der Wal, S.; Schoenmakers, P.J.

    2017-01-01

    Recent advancements in separation science have resulted in the commercialization of multidimensional separation systems that provide higher peak capacities and, hence, enable a more-detailed characterization of complex mixtures. In particular, two powerful analytical tools are increasingly used by

  7. Multidimensional chromatography coupled to mass spectrometry in analysing complex proteomics samples

    NARCIS (Netherlands)

    Horvatovich, Peter; Hoekman, Berend; Govorukhina, Natalia; Bischoff, Rainer

    Multidimensional chromatography coupled to mass spectrometry (LC(n)-MS) provides more separation power and an extended measured dynamic concentration range to analyse complex proteomics samples than one dimensional liquid chromatography coupled to mass spectrometry (1D-LC-MS). This review gives an

  8. performance liquid chromatography

    African Journals Online (AJOL)

    user

    2010-11-22

    Nov 22, 2010 ... ISSN 1684–5315 © 2010 Academic Journals. Full Length Research Paper. Determination ... Key words: Processed food, high-performance liquid chromatography, acrylamide, health hazard. INTRODUCTION. In the year 2002, the ... potatoes, breakfast cereals etc. It was thus confirmed that acrylamide has ...

  9. Micellar liquid chromatography

    International Nuclear Information System (INIS)

    Basova, Elena M; Ivanov, Vadim M; Shpigun, Oleg A

    1999-01-01

    Background and possibilities of practical applications of micellar liquid chromatography (MLC) are considered. Various retention models in MLC, the effects of the nature and concentration of surfactants and organic modifiers, pH, temperature and ionic strength on the MLC efficiency and selectivity are discussed. The advantages and limitations of MLC are demonstrated. The performance of MLC is critically evaluated in relationship to the reversed-phase HPLC and ion-pair chromatography. The potential of application of MLC for the analysis of pharmaceuticals including that in biological fluids and separation of inorganic anions, transition metal cations, metal chelates and heteropoly compounds is described. The bibliography includes 146 references.

  10. Quantification of free and total bisphenol A and bisphenol B in human urine by dispersive liquid-liquid microextraction (DLLME) and heart-cutting multidimensional gas chromatography-mass spectrometry (MD-GC/MS).

    Science.gov (United States)

    Cunha, S C; Fernandes, J O

    2010-11-15

    A novel method combining dispersive liquid-liquid microextraction (DLLME) and heart-cutting multidimensional gas chromatography coupled to mass spectrometry was developed for the determination of free and total bisphenol A (BPA) and bisphenol B (BPB) in human urine samples. The DLLME procedure combines extraction, derivatization and concentration of the analytes into one step. Several important variables influencing the extraction efficiency and selectivity such as nature and volume of extractive and dispersive solvents as well as the amount of acetylating reagent were investigated. The temperature and time to hydrolyze BPA and BPB conjugates with a β-glucuronidase and sulfatase enzyme preparation were also studied. Under the optimized conditions good efficiency extraction (71-93%) and acceptable total DLLME yields (56-77%) were obtained for both analytes. Matrix-matched calibration curves were linear with correlation coefficients higher than 0.996 in the range level 0.1-5 μg/l, and the relative standard deviations (%RSD) were lower than 20% (n=6). The limits of detection were 0.03 and 0.05 μg/l for BPA and BPB, respectively. The applicability of the proposed method for determining urinary free and total BPA and BPB was assessed by analyzing the human urine of a group of 20 volunteers. Free BPA was detected in 45% of the sample whereas total BPA was detected in 85% of the samples at concentrations ranging between 0.39 and 4.99 μg/l. BPB was detected in conjugated form in two samples. Copyright © 2010 Elsevier B.V. All rights reserved.

  11. Identification of marker proteins for the adulteration of meat products with soybean proteins by multidimensional liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Leitner, Alexander; Castro-Rubio, Florentina; Marina, Maria Luisa; Lindner, Wolfgang

    2006-09-01

    Soybean proteins are frequently added to processed meat products for economic reasons and to improve their functional properties. Monitoring of the addition of soybean protein to meat products is of high interest due to the existence of regulations forbidding or limiting the amount of soybean proteins that can be added during the processing of meat products. We have used chromatographic prefractionation on the protein level by perfusion liquid chromatography to isolate peaks of interest from extracts of soybean protein isolate (SPI) and of meat products containing SPI. After enzymatic digestion using trypsin, the collected fractions were analyzed by nanoflow liquid chromatography-tandem mass spectrometry. Several variants and subunits of the major seed proteins, glycinin and beta-conglycinin, were identified in SPI, along with two other proteins. In soybean-protein-containing meat samples, different glycinin A subunits could be identified from the peak discriminating between samples with and without soybean proteins added. Among those, glycinin G4 subunit A4 was consistently found in all samples. Consequently, this protein (subunit) can be used as a target for new analytical techniques in the course of identifying the addition of soybean protein to meat products.

  12. Novel comprehensive multidimensional liquid chromatography approach for elucidation of the microbosphere of shikimate-producing Escherichia coli SP1.1/pKD15.071 strain.

    Science.gov (United States)

    Cacciola, Francesco; Mangraviti, Domenica; Rigano, Francesca; Donato, Paola; Dugo, Paola; Mondello, Luigi; Cortes, Hernan J

    2018-06-01

    Shikimic acid is a intermediate of aromatic amino acid biosynthesis and the preferred starting material for production of the most commonly prescribed anti-influenza drug, Tamiflu. Its six-membered carbocyclic ring is adorned with several chiral centers and various functionalities, making shikimic acid a valuable chiral synthon. When microbially-produced, in addition to shikimic acid, numerous other metabolites are exported out of the cytoplasm and accumulate in the culture medium. This extracellular matrix of metabolites is referred to as the microbosphere. Due to the high sample complexity, in this study, the microbosphere of shikimate-producing Escherichia coli SP1.1/pKD15.071 was analyzed by liquid chromatography and comprehensive two-dimensional liquid chromatography coupled to photodiode array and mass spectrometry detection. GC analysis of the trimethylsilyl derivatives was also carried out in order to support the elucidation of the selected metabolites in the microbosphere. The elucidation of the metabolic fraction of this bacterial strain might be of valid aid for improving, through genetic changes, the concentration and yield of shikimic acid synthesized from glucose. Graphical abstract.

  13. Introduction to modern liquid chromatography

    National Research Council Canada - National Science Library

    Snyder, Lloyd R; Kirkland, J. J; Dolan, John W

    2010-01-01

    "High-performance liquid chromatography (HPLC) is today the leading technique for chemical analysis and related applications, with an ability to separate, analyze, and/or purify virtually any sample...

  14. Liquid chromatography in migration studies

    International Nuclear Information System (INIS)

    Carlsen, L.; Batsberg, W.

    1982-01-01

    Liquid chromatography ahs been suggested as a facile experimental technique to determine important physico-chemical properties, as permeability, porosity, dispersion-, diffusion-, and sorption charcteristics for geological material as chalk samples. The feasibility of the trechnique as a rapid method to evaluate the possible influence of changes in ground water composition on the migration behavior of radionuclides has been demonstrated

  15. Liquid phase chromatography on microchips

    DEFF Research Database (Denmark)

    Kutter, Jörg Peter

    2012-01-01

    explosive development of, in particular, chromatographic separation systems on microchips, has, however, slowed down in recent years. This review takes a closer, critical look at how liquid phase chromatography has been implemented in miniaturized formats over the past several years, what is important...

  16. Simultaneous determination of bisphenol A and bisphenol B in beverages and powdered infant formula by dispersive liquid-liquid micro-extraction and heart-cutting multidimensional gas chromatography-mass spectrometry.

    Science.gov (United States)

    Cunha, S C; Almeida, C; Mendes, E; Fernandes, J O

    2011-04-01

    The purpose of this study was to establish a reliable, cost-effective, fast and simple method to quantify simultaneously both bisphenol A (BPA) and bisphenol B (BPB) in liquid food matrixes such as canned beverages (soft drinks and beers) and powdered infant formula using dispersive liquid-liquid micro-extraction (DLLME) with in-situ derivatisation coupled with heart-cutting gas chromatography-mass spectrometry (GC-MS). For the optimisation of the DLLME procedure different amounts of various extractive and dispersive solvents as well as different amounts of the derivative reagent were compared for their effects on extraction efficiency and yields. The optimised procedure consisted of the injection of a mixture containing tetrachloroethylene (extractant), acetonitrile (dispersant) and acetic anhydride (derivatising reagent) directly into an aliquot of beverage samples or into an aqueous extract of powdered milk samples obtained after a pretreatment of the samples. Given the compatibility of the solvents used, and the low volumes involved, the procedure was easily associated with GC-MS end-point determination, which was accomplished by means of an accurate GC dual column (heart-cutting) technique. Careful optimisation of heart-cutting GC-MS conditions, namely pressure of front and auxiliary inlets, have resulted in a good analytical performance. The linearity of the matrix-matched calibration curves was acceptable, with coefficients of determination (r2) always higher than 0.99. Average recoveries of the BPA and BPB spiked at two concentration levels into beverages and powdered infant formula ranged from 68% to 114% and the relative standard deviation (RSD) was canned beverages were 5.0 and 2.0 ng l(-1) for BPA and BPB, respectively, whereas LOD in powdered infant formula were 60.0 and 30.0 ng l(-1), respectively. The limits of quantification (LOQ) in canned beverages were 10.0 and 7.0 ng l-1 for BPA and BPB, respectively, whereas LOQ in powdered infant formula were

  17. Comprehensive analysis of a multidimensional liquid chromatography mass spectrometry dataset acquired on a quadrupole selecting, quadrupole collision cell, time-of-flight mass spectrometer: I. How much of the data is theoretically interpretable by search engines?

    Science.gov (United States)

    Chalkley, Robert J; Baker, Peter R; Hansen, Kirk C; Medzihradszky, Katalin F; Allen, Nadia P; Rexach, Michael; Burlingame, Alma L

    2005-08-01

    An in-depth analysis of a multidimensional chromatography-mass spectrometry dataset acquired on a quadrupole selecting, quadrupole collision cell, time-of-flight (QqTOF) geometry instrument was carried out. A total of 3269 CID spectra were acquired. Through manual verification of database search results and de novo interpretation of spectra 2368 spectra could be confidently determined as predicted tryptic peptides. A detailed analysis of the non-matching spectra was also carried out, highlighting what the non-matching spectra in a database search typically are composed of. The results of this comprehensive dataset study demonstrate that QqTOF instruments produce information-rich data of which a high percentage of the data is readily interpretable.

  18. [High-performance liquid-liquid chromatography in beverage analysis].

    Science.gov (United States)

    Bricout, J; Koziet, Y; de Carpentrie, B

    1978-01-01

    Liquid liquid chromatography was performed with columns packed with stationary phases chemically bonded to silica microparticules. These columns show a high efficiency and are used very easily. Flavouring compounds like aromatic aldehydes which have a low volatility were analyzed in brandy using a polar phase alkylnitrile. Sapid substances like amarogentin in Gentiana lutea or glyryrrhizin in Glycyrrhiza glabra were determined by reversed phase chromatography. Finally ionizable substances like synthetic dyes can be analyzed by paired ion chromatography witha non polar stationary phase.

  19. Gradient High Performance Liquid Chromatography Method ...

    African Journals Online (AJOL)

    Purpose: To develop a gradient high performance liquid chromatography (HPLC) method for the simultaneous determination of phenylephrine (PHE) and ibuprofen (IBU) in solid ..... nimesulide, phenylephrine. Hydrochloride, chlorpheniramine maleate and caffeine anhydrous in pharmaceutical dosage form. Acta Pol.

  20. UHPLC: The Greening Face of Liquid Chromatography

    OpenAIRE

    Cielecka-Piontek, Judyta; Zalewski, Przemys?aw; Jeli?ska, Anna; Garbacki, Piotr

    2013-01-01

    Pharmaceutical analysis based on chromatographic separation is an important part of studies aimed at developing routine quality analysis of drugs. High-performance liquid chromatography (HPLC) is one of the main analytical techniques recommended for drug analysis. Although it meets many criteria vital for analysis, it is time-consuming and uses a relatively high amount of organic solvents compared to other analytical techniques. Recently, Ultra-high-performance liquid chromatography (UHPLC) h...

  1. Hyphenated techniques in multidimensional gas chromatography for analysis of wine aroma and related odorants

    OpenAIRE

    Chin, Sung Tong

    2017-01-01

    The advent of analytical multidimensional gas chromatography (MDGC) techniques, with recent development in comprehensive two-dimensional gas chromatography (GC×GC) as well as microfluidic technology in conventional heart-cut MDGC, has achieved excellent separation efficiency for advanced characterization of complex volatile and semi-volatile samples, which is unlikely to be accomplished by single dimensional chromatography. This dissertation work has highlighted the potential opportunities fo...

  2. Liquid chromatography detection unit, system, and method

    Science.gov (United States)

    Derenzo, Stephen E.; Moses, William W.

    2015-10-27

    An embodiment of a liquid chromatography detection unit includes a fluid channel and a radiation detector. The radiation detector is operable to image a distribution of a radiolabeled compound as the distribution travels along the fluid channel. An embodiment of a liquid chromatography system includes an injector, a separation column, and a radiation detector. The injector is operable to inject a sample that includes a radiolabeled compound into a solvent stream. The position sensitive radiation detector is operable to image a distribution of the radiolabeled compound as the distribution travels along a fluid channel. An embodiment of a method of liquid chromatography includes injecting a sample that comprises radiolabeled compounds into a solvent. The radiolabeled compounds are then separated. A position sensitive radiation detector is employed to image distributions of the radiolabeled compounds as the radiolabeled compounds travel along a fluid channel.

  3. Ionic liquid stationary phases for gas chromatography.

    Science.gov (United States)

    Poole, Colin F; Poole, Salwa K

    2011-04-01

    This article provides a summary of the development of ionic liquids as stationary phases for gas chromatography beginning with early work on packed columns that established details of the retention mechanism and established working methods to characterize selectivity differences compared with molecular stationary phases through the modern development of multi-centered cation and cross-linked ionic liquids for high-temperature applications in capillary gas chromatography. Since there are many reviews on ionic liquids dealing with all aspects of their chemical and physical properties, the emphasis in this article is placed on the role of gas chromatography played in the design of ionic liquids of low melting point, high thermal stability, high viscosity, and variable selectivity for separations. Ionic liquids provide unprecedented opportunities for extending the selectivity range and temperature-operating range of columns for gas chromatography, an area of separation science that has otherwise been almost stagnant for over a decade. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Chemometric Strategies for Peak Detection and Profiling from Multidimensional Chromatography.

    Science.gov (United States)

    Navarro-Reig, Meritxell; Bedia, Carmen; Tauler, Romà; Jaumot, Joaquim

    2018-04-03

    The increasing complexity of omics research has encouraged the development of new instrumental technologies able to deal with these challenging samples. In this way, the rise of multidimensional separations should be highlighted due to the massive amounts of information that provide with an enhanced analyte determination. Both proteomics and metabolomics benefit from this higher separation capacity achieved when different chromatographic dimensions are combined, either in LC or GC. However, this vast quantity of experimental information requires the application of chemometric data analysis strategies to retrieve this hidden knowledge, especially in the case of nontargeted studies. In this work, the most common chemometric tools and approaches for the analysis of this multidimensional chromatographic data are reviewed. First, different options for data preprocessing and enhancement of the instrumental signal are introduced. Next, the most used chemometric methods for the detection of chromatographic peaks and the resolution of chromatographic and spectral contributions (profiling) are presented. The description of these data analysis approaches is complemented with enlightening examples from omics fields that demonstrate the exceptional potential of the combination of multidimensional separation techniques and chemometric tools of data analysis. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Validated High Performance Liquid Chromatography Method for ...

    African Journals Online (AJOL)

    Purpose: To develop a simple, rapid and sensitive high performance liquid chromatography (HPLC) method for the determination of cefadroxil monohydrate in human plasma. Methods: Schimadzu HPLC with LC solution software was used with Waters Spherisorb, C18 (5 μm, 150mm × 4.5mm) column. The mobile phase ...

  6. Electronic spectral detection in liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Biggs, Wilton R. [ChevronTexaco Chemical Co., P. O. Box 1627, Richmond, CA 94802 (United States); Fetzer, John C. [Fetzpahs Consulting, 1283 Santa Fe St., Hercules, CA 94547 (United States)

    2002-07-01

    The use of absorbance and fluorescence spectrometers as liquid chromatography detectors is described. These detectors offer sensitive detection that can also identify the peaks in a chromatogram. Many examples, mainly from the separation of polycyclic aromatic hydrocarbons, are given that show the selectivity and usefulness of these detectors. (orig.)

  7. Instrument platforms for nano liquid chromatography

    Czech Academy of Sciences Publication Activity Database

    Šesták, Jozef; Moravcová, Dana; Kahle, Vladislav

    2015-01-01

    Roč. 1421, NOV (2015), s. 2-17 ISSN 0021-9673 R&D Projects: GA MV VG20112015021 Institutional support: RVO:68081715 Keywords : nano liquid chromatography * splitless gradient generation * nano LC platforms Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.926, year: 2015 http://hdl.handle.net/11104/0250900

  8. Instrument platforms for nano liquid chromatography.

    Science.gov (United States)

    Šesták, Jozef; Moravcová, Dana; Kahle, Vladislav

    2015-11-20

    The history of liquid chromatography started more than a century ago and miniaturization and automation are two leading trends in this field. Nanocolumn liquid chromatography (nano LC) and largely synonymous capillary liquid chromatography (capillary LC) are the most recent results of this process where miniaturization of column dimensions and sorbent particle size play crucial role. Very interesting results achieved in the research of extremely miniaturized LC columns at the end of the last century lacked distinctive raison d'être and only advances in mass spectrometry brought a real breakthrough. Configuration of nano LC-electrospray ionization mass spectrometry (LC-ESI-MS) has become a basic tool in bioanalytical chemistry, especially in proteomics. This review discusses and summarizes past and current trends in the realization of nano liquid chromatography (nano LC) platforms. Special attention is given to the mobile phase delivery under nanoflow rates (isocratic, gradient) and sample injection to the nanocolumn. Available detection techniques applied in nano LC separations are also briefly discussed. We followed up the key themes from the original scientific reports over gradual improvements up to the contemporary commercial solutions. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Ultra Performance Liquid Chromatography Tandem Mass ...

    African Journals Online (AJOL)

    NICOLAAS

    drugs alone.16. After a single oral dose of 120–800 mg of NTB in healthy sub- jects in a fasting state the peak plasma NTB concentration (tmax) was found to be 4–7 h, with a half-life of approximately 9–17 h.17 ... performance liquid chromatography mass spectrometry/mass .... to the likely biological plasma constituents.

  10. High Performance Liquid Chromatography Experiments to Undergraduate Laboratories

    Science.gov (United States)

    Kissinger, Peter T.; And Others

    1977-01-01

    Reviews the principles of liquid chromatography with electrochemical detection (LCEC), an analytical technique that incorporates the advantages of both liquids chromatography and electrochemistry. Also suggests laboratory experiments using this technique. (MLH)

  11. Development of a high performance liquid chromatography method ...

    African Journals Online (AJOL)

    Development of a high performance liquid chromatography method for simultaneous ... Purpose: To develop and validate a new low-cost high performance liquid chromatography (HPLC) method for ..... Several papers have reported the use of ...

  12. Optimizing separations in online comprehensive two‐dimensional liquid chromatography

    OpenAIRE

    Pirok, Bob W.J.; Gargano, Andrea F.G.; Schoenmakers, Peter J.

    2017-01-01

    Abstract Online comprehensive two‐dimensional liquid chromatography has become an attractive option for the analysis of complex nonvolatile samples found in various fields (e.g. environmental studies, food, life, and polymer sciences). Two‐dimensional liquid chromatography complements the highly popular hyphenated systems that combine liquid chromatography with mass spectrometry. Two‐dimensional liquid chromatography is also applied to the analysis of samples that are not compatible with mass...

  13. Comparative determination of phenytoin by spectrophotometry, gas chromatography, liquid chromatography, enzyme immunoassay, and radioimmunoassay

    International Nuclear Information System (INIS)

    Castro, A.; Ibanez, J.; DiCesare, J.L.; Adams, R.F.; Malkus, H.

    1978-01-01

    Sera from patients being treated with phenytoin were analyzed for the drug by spectrophotometry, gas chromatography, radioimmunoasay, enzyme immunoassay, and liquid chromatography. The assay values obtained were intercompared statistically. Enzyme immunoassay and liquid chromatography appear to be attractive alternatives to the more traditional methods of spectrophotometry and gas chromatography. Our radioimmunoassay data correlated poorly with results by the four other methods

  14. High perfomance liquid chromatography in pharmaceutical analyses.

    Science.gov (United States)

    Nikolin, Branko; Imamović, Belma; Medanhodzić-Vuk, Saira; Sober, Miroslav

    2004-05-01

    In testing the pre-sale procedure the marketing of drugs and their control in the last ten years, high performance liquid chromatography replaced numerous spectroscopic methods and gas chromatography in the quantitative and qualitative analysis. In the first period of HPLC application it was thought that it would become a complementary method of gas chromatography, however, today it has nearly completely replaced gas chromatography in pharmaceutical analysis. The application of the liquid mobile phase with the possibility of transformation of mobilized polarity during chromatography and all other modifications of mobile phase depending upon the characteristics of substance which are being tested, is a great advantage in the process of separation in comparison to other methods. The greater choice of stationary phase is the next factor which enables realization of good separation. The separation line is connected to specific and sensitive detector systems, spectrafluorimeter, diode detector, electrochemical detector as other hyphernated systems HPLC-MS and HPLC-NMR, are the basic elements on which is based such wide and effective application of the HPLC method. The purpose high performance liquid chromatography (HPLC) analysis of any drugs is to confirm the identity of a drug and provide quantitative results and also to monitor the progress of the therapy of a disease.1) Measuring presented on the Fig. 1. is chromatogram obtained for the plasma of depressed patients 12 h before oral administration of dexamethasone. It may also be used to further our understanding of the normal and disease process in the human body trough biomedical and therapeutically research during investigation before of the drugs registration. The analyses of drugs and metabolites in biological fluids, particularly plasma, serum or urine is one of the most demanding but one of the most common uses of high performance of liquid chromatography. Blood, plasma or serum contains numerous endogenous

  15. Recent development of ionic liquid stationary phases for liquid chromatography.

    Science.gov (United States)

    Shi, Xianzhe; Qiao, Lizhen; Xu, Guowang

    2015-11-13

    Based on their particular physicochemical characteristics, ionic liquids have been widely applied in many fields of analytical chemistry. Many types of ionic liquids were immobilized on a support like silica or monolith as stationary phases for liquid chromatography. Moreover, different approaches were developed to bond covalently ionic liquids onto the supporting materials. The obtained ionic liquid stationary phases show multi-mode mechanism including hydrophobic, hydrophilic, hydrogen bond, anion exchange, π-π, and dipole-dipole interactions. Therefore, they could be used in different chromatographic modes including ion-exchange, RPLC, NPLC and HILIC to separate various classes of compounds. This review mainly summarizes the immobilized patterns and types of ionic liquid stationary phases, their retention mechanisms and applications in the recent five years. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. UHPLC: The Greening Face of Liquid Chromatography.

    Science.gov (United States)

    Cielecka-Piontek, Judyta; Zalewski, Przemysław; Jelińska, Anna; Garbacki, Piotr

    2013-01-01

    Pharmaceutical analysis based on chromatographic separation is an important part of studies aimed at developing routine quality analysis of drugs. High-performance liquid chromatography (HPLC) is one of the main analytical techniques recommended for drug analysis. Although it meets many criteria vital for analysis, it is time-consuming and uses a relatively high amount of organic solvents compared to other analytical techniques. Recently, Ultra-high-performance liquid chromatography (UHPLC) has been frequently proposed as an alternative to HPLC, which means introducing an environment-friendly approach to drug analysis achieved by reducing the consumption of solvents. It also offers greater chromatographic resolution and higher sensitivity as well as requiring less time due to faster analysis. This review focuses on the basics of UHPLC, compares that technique with HPLC and discusses the possibilities of applying UHPLC for the analysis of different pharmaceuticals and biopharmaceuticals.

  17. High performance liquid chromatography in pharmaceutical analyses

    Directory of Open Access Journals (Sweden)

    Branko Nikolin

    2004-05-01

    Full Text Available In testing the pre-sale procedure the marketing of drugs and their control in the last ten years, high performance liquid chromatographyreplaced numerous spectroscopic methods and gas chromatography in the quantitative and qualitative analysis. In the first period of HPLC application it was thought that it would become a complementary method of gas chromatography, however, today it has nearly completely replaced gas chromatography in pharmaceutical analysis. The application of the liquid mobile phase with the possibility of transformation of mobilized polarity during chromatography and all other modifications of mobile phase depending upon the characteristics of substance which are being tested, is a great advantage in the process of separation in comparison to other methods. The greater choice of stationary phase is the next factor which enables realization of good separation. The separation line is connected to specific and sensitive detector systems, spectrafluorimeter, diode detector, electrochemical detector as other hyphernated systems HPLC-MS and HPLC-NMR, are the basic elements on which is based such wide and effective application of the HPLC method. The purpose high performance liquid chromatography(HPLC analysis of any drugs is to confirm the identity of a drug and provide quantitative results and also to monitor the progress of the therapy of a disease.1 Measuring presented on the Fig. 1. is chromatogram obtained for the plasma of depressed patients 12 h before oral administration of dexamethasone. It may also be used to further our understanding of the normal and disease process in the human body trough biomedical and therapeutically research during investigation before of the drugs registration. The analyses of drugs and metabolites in biological fluids, particularly plasma, serum or urine is one of the most demanding but one of the most common uses of high performance of liquid chromatography. Blood, plasma or

  18. Ion exchange and liquid column chromatography

    International Nuclear Information System (INIS)

    Walton, H.F.

    1980-01-01

    Major accomplishments in liquid chromatography for the past two years and reported in journals available to December 31, 1979 are reviewed. Emphasis has been placed on principles and methodology with some representative examples of application included. Applications are illustrated in two rather lenghtly tables, one covering inorganic ions and the other covering organic compounds. 544 references, 8 books, and 15 reviews are listed in the bibliography

  19. Flow Rates in Liquid Chromatography, Gas Chromatography and Supercritical Fluid Chromatography: A Tool for Optimization

    Directory of Open Access Journals (Sweden)

    Joris Meurs

    2016-08-01

    Full Text Available This paper aimed to develop a standalone application for optimizing flow rates in liquid chromatography (LC, gas chromatography (GC and supercritical fluid chromatography (SFC. To do so, Van Deemter’s equation, Knox’ equation and Golay’s equation were implemented in a MATLAB script and subsequently a graphical user interface (GUI was created. The application will show the optimal flow rate or linear velocity and the corresponding plate height for the set input parameters. Furthermore, a plot will be shown in which the plate height is plotted against the linear flow velocity. Hence, this application will give optimized flow rates for any set conditions with minimal effort.

  20. A multidimensional high performance liquid chromatography method coupled with amperometric detection using a boron-doped diamond electrode for the simultaneous determination of sulfamethoxazole and trimethoprim in bovine milk

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Leonardo S.; Moraes, Marcela C. de; Rocha-Filho, Romeu C.; Fatibello-Filho, Orlando [Departamento de Quimica, Universidade Federal de Sao Carlos, C.P. 676, 13560-970 Sao Carlos - SP (Brazil); Cass, Quezia B., E-mail: quezia@pesquisador.cnpq.br [Departamento de Quimica, Universidade Federal de Sao Carlos, C.P. 676, 13560-970 Sao Carlos - SP (Brazil)

    2009-11-10

    The development and validation of a multidimensional HPLC method using an on-line clean-up column coupled with amperometric detection employing a boron-doped diamond (BDD) electrode for the simultaneous determination of sulfamethoxazole (SMX) and trimethoprim (TMP) in bovine milk are presented. Aliquots of pre-prepared skim-milk samples were directly injected into a RAM octyl-BSA column in order to remove proteins that otherwise would interfere with milk analysis. After exclusion of the milk proteins, SMX and TMP were transferred to the analytical column (an octyl column) and the separation of the compounds from one another and from other endogenous milk components was achieved. SMX and TMP were detected amperometrically at 1.25 V vs. Ag/AgCl (3.0 mol L{sup -1} KCl). Results with good linearity in the concentration ranges 50-800 and 25-400 {mu}g L{sup -1} for SMX and TMP, respectively, were obtained and no fouling of the BDD electrode was observed within the experimental period of several hours. The intra- and inter-assay coefficients of variation were less than 10% for both drugs and the obtained LOD values for SMX and TMP were 25.0 and 15.0 {mu}g L{sup -1}, respectively.

  1. A multidimensional high performance liquid chromatography method coupled with amperometric detection using a boron-doped diamond electrode for the simultaneous determination of sulfamethoxazole and trimethoprim in bovine milk

    International Nuclear Information System (INIS)

    Andrade, Leonardo S.; Moraes, Marcela C. de; Rocha-Filho, Romeu C.; Fatibello-Filho, Orlando; Cass, Quezia B.

    2009-01-01

    The development and validation of a multidimensional HPLC method using an on-line clean-up column coupled with amperometric detection employing a boron-doped diamond (BDD) electrode for the simultaneous determination of sulfamethoxazole (SMX) and trimethoprim (TMP) in bovine milk are presented. Aliquots of pre-prepared skim-milk samples were directly injected into a RAM octyl-BSA column in order to remove proteins that otherwise would interfere with milk analysis. After exclusion of the milk proteins, SMX and TMP were transferred to the analytical column (an octyl column) and the separation of the compounds from one another and from other endogenous milk components was achieved. SMX and TMP were detected amperometrically at 1.25 V vs. Ag/AgCl (3.0 mol L -1 KCl). Results with good linearity in the concentration ranges 50-800 and 25-400 μg L -1 for SMX and TMP, respectively, were obtained and no fouling of the BDD electrode was observed within the experimental period of several hours. The intra- and inter-assay coefficients of variation were less than 10% for both drugs and the obtained LOD values for SMX and TMP were 25.0 and 15.0 μg L -1 , respectively.

  2. A multidimensional high performance liquid chromatography method coupled with amperometric detection using a boron-doped diamond electrode for the simultaneous determination of sulfamethoxazole and trimethoprim in bovine milk.

    Science.gov (United States)

    Andrade, Leonardo S; de Moraes, Marcela C; Rocha-Filho, Romeu C; Fatibello-Filho, Orlando; Cass, Quezia B

    2009-11-10

    The development and validation of a multidimensional HPLC method using an on-line clean-up column coupled with amperometric detection employing a boron-doped diamond (BDD) electrode for the simultaneous determination of sulfamethoxazole (SMX) and trimethoprim (TMP) in bovine milk are presented. Aliquots of pre-prepared skim-milk samples were directly injected into a RAM octyl-BSA column in order to remove proteins that otherwise would interfere with milk analysis. After exclusion of the milk proteins, SMX and TMP were transferred to the analytical column (an octyl column) and the separation of the compounds from one another and from other endogenous milk components was achieved. SMX and TMP were detected amperometrically at 1.25V vs. Ag/AgCl (3.0molL(-1) KCl). Results with good linearity in the concentration ranges 50-800 and 25-400microgL(-1) for SMX and TMP, respectively, were obtained and no fouling of the BDD electrode was observed within the experimental period of several hours. The intra- and inter-assay coefficients of variation were less than 10% for both drugs and the obtained LOD values for SMX and TMP were 25.0 and 15.0microgL(-1), respectively.

  3. Application of ionic liquids in liquid chromatography and electrodriven separation.

    Science.gov (United States)

    Huang, Yi; Yao, Shun; Song, Hang

    2013-08-01

    Ionic liquids (ILs) are salts in the liquid state at ambient temperature, which are nonvolatile, nonflammable with high thermal stability and dissolve easily for a wide range of inorganic and organic materials. As a kind of potential green solvent, they show high efficiency and selectivity in the field of separation research, especially in instrumental analysis. Thus far, ILs have been successfully applied by many related researchers in high-performance liquid chromatography and capillary electrophoresis as chromatographic stationary phases, mobile phase additives or electroosmotic flow modifiers. This paper provides a detailed review of these applications in the study of natural products, foods, drugs and other fine chemicals. Furthermore, the prospects of ILs in liquid chromatographic and electrodriven techniques are discussed.

  4. Spillage detector for liquid chromatography systems

    Science.gov (United States)

    Jarvis, M. J.; Fulton, D. S. (Inventor)

    1986-01-01

    A spillage detector device for use in conjunction with fractionation of liquid chromatography systems which includes a spillage recieving enclosure beneath the fractionation area is described. A sensing device having a plurality of electrodes of alternating polarity is mounted within the spillage recieving enclosure. Detection circuitry, responsive to conductivity between electrodes, is operatively connected to the sensing device. The detection circuitry feeds into the output circuitry. The output circuit has relaying and switching circuitry directed to a solenoid, an alarm system and a pump. The solenoid is connected to the pliable conduit of the chromatography system. The alarm system comprises an audio alarm and a visual signal. A 115-volt power system interconnected with the pump, the solenoid, the sensing device, and the detection and output circuitry.

  5. Characterisation of uremic "Middle molecular"fractions by gas chromatography mass spectrometry, isotachophoresis, and liquid chromatography

    NARCIS (Netherlands)

    Schoots, A.C.; Mikkers, F.E.P.; Claessens, H.A.; Smet, de R.; Landschoot, van N.; Ringoir, S.M.G.

    1982-01-01

    Uremic ultrafiltrates (and normal serum, for comparison) were fractionated by means of gel filtration. The collected fractions were further investigated by combined analytical techniques: "high- performance" liquid chromatography, gas chromatography, mass spectrometry, and isotachophoresis.

  6. Liquid chromatography - mass spectrometry analysis of pharmaceuticals

    International Nuclear Information System (INIS)

    Macasek, F.

    2003-01-01

    The drugs represent mostly non-volatile and thermally labile solutes, often available only in small amounts like it is in case of radiopharmaceuticals. Therefor, the favourable separation techniques for such compounds are HPLC, capillary electrophoresis and also TLC 1. Liquid chromatography with mass spectrometric detector (LC/MS) is especially powerful for their microanalysis. Mass spectrometry separating the ions in high vacuum was presumably used as detector for gas chromatography effluent but the on-line coupling with liquid eluant flow 0.1-1 mL/min is far more challenging. New types of ion sources were constructed for simultaneous removal of solvent and ionisation of solutes at atmospheric pressure (API). At present, a relatively wide choice of successfully designed commercial equipment is available either for small organic molecules and larger biomolecules (Perkin-Elmer, Agilent, Jeol, Bruker Daltonics, ThermoQuest, Shimadzu). The features of the LC/MS systems are presented. LC/MS as a new quality control tool for [F-18]fluorodeoxyglucose (FDG) radiopharmaceutical, which has became the most spread radiopharmaceutical for positron emission tomography (PET), was proposed. Other applications of the LC/MS are reviewed. (author)

  7. Optimizing separations in online comprehensive two‐dimensional liquid chromatography

    Science.gov (United States)

    Gargano, Andrea F.G.; Schoenmakers, Peter J.

    2017-01-01

    Abstract Online comprehensive two‐dimensional liquid chromatography has become an attractive option for the analysis of complex nonvolatile samples found in various fields (e.g. environmental studies, food, life, and polymer sciences). Two‐dimensional liquid chromatography complements the highly popular hyphenated systems that combine liquid chromatography with mass spectrometry. Two‐dimensional liquid chromatography is also applied to the analysis of samples that are not compatible with mass spectrometry (e.g. high‐molecular‐weight polymers), providing important information on the distribution of the sample components along chemical dimensions (molecular weight, charge, lipophilicity, stereochemistry, etc.). Also, in comparison with conventional one‐dimensional liquid chromatography, two‐dimensional liquid chromatography provides a greater separation power (peak capacity). Because of the additional selectivity and higher peak capacity, the combination of two‐dimensional liquid chromatography with mass spectrometry allows for simpler mixtures of compounds to be introduced in the ion source at any given time, improving quantitative analysis by reducing matrix effects. In this review, we summarize the rationale and principles of two‐dimensional liquid chromatography experiments, describe advantages and disadvantages of combining different selectivities and discuss strategies to improve the quality of two‐dimensional liquid chromatography separations. PMID:29027363

  8. Optimizing separations in online comprehensive two-dimensional liquid chromatography.

    Science.gov (United States)

    Pirok, Bob W J; Gargano, Andrea F G; Schoenmakers, Peter J

    2018-01-01

    Online comprehensive two-dimensional liquid chromatography has become an attractive option for the analysis of complex nonvolatile samples found in various fields (e.g. environmental studies, food, life, and polymer sciences). Two-dimensional liquid chromatography complements the highly popular hyphenated systems that combine liquid chromatography with mass spectrometry. Two-dimensional liquid chromatography is also applied to the analysis of samples that are not compatible with mass spectrometry (e.g. high-molecular-weight polymers), providing important information on the distribution of the sample components along chemical dimensions (molecular weight, charge, lipophilicity, stereochemistry, etc.). Also, in comparison with conventional one-dimensional liquid chromatography, two-dimensional liquid chromatography provides a greater separation power (peak capacity). Because of the additional selectivity and higher peak capacity, the combination of two-dimensional liquid chromatography with mass spectrometry allows for simpler mixtures of compounds to be introduced in the ion source at any given time, improving quantitative analysis by reducing matrix effects. In this review, we summarize the rationale and principles of two-dimensional liquid chromatography experiments, describe advantages and disadvantages of combining different selectivities and discuss strategies to improve the quality of two-dimensional liquid chromatography separations. © 2017 The Authors. Journal of Separation Science published by WILEY-VCH Verlag GmbH & Co. KGaA.

  9. Comprehensive two-dimensional liquid chromatography: Ion chromatography × reversed-phase liquid chromatography for separation of low-molar-mass organic acids

    NARCIS (Netherlands)

    Brudin, S.S.; Shellie, R.A.; Haddad, P.R.; Schoenmakers, P.J.

    2010-01-01

    In the work presented here a novel approach to comprehensive two-dimensional liquid chromatography is evaluated. Ion chromatography is chosen for the first-dimension separation and reversed-phase liquid chromatography is chosen for the second-dimension separation mode. The coupling of these modes is

  10. Microchip-based monolithic column for high performance liquid chromatography

    Data.gov (United States)

    National Aeronautics and Space Administration — We have developed microchip based monolithic columns that can be used for liquid chromatography of small organic molecules, as well as, macromolecules such as...

  11. High Performance Liquid Chromatography of Vitamin A: A Quantitative Determination.

    Science.gov (United States)

    Bohman, Ove; And Others

    1982-01-01

    Experimental procedures are provided for the quantitative determination of Vitamin A (retinol) in food products by analytical liquid chromatography. Standard addition and calibration curve extraction methods are outlined. (SK)

  12. A generalized theory of chromatography and multistep liquid extraction

    Science.gov (United States)

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

    2017-03-01

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

  13. Overview of online two-dimensional liquid chromatography based on cell membrane chromatography for screening target components from traditional Chinese medicines.

    Science.gov (United States)

    Muhammad, Saqib; Han, Shengli; Xie, Xiaoyu; Wang, Sicen; Aziz, Muhammad Majid

    2017-01-01

    Cell membrane chromatography is a simple, specific, and time-saving technique for studying drug-receptor interactions, screening of active components from complex mixtures, and quality control of traditional Chinese medicines. However, the short column life, low sensitivity, low column efficiency (so cannot resolve satisfactorily mixture of compounds), low peak capacity, and inefficient in structure identification were bottleneck in its application. Combinations of cell membrane chromatography with multidimensional chromatography such as two-dimensional liquid chromatography and high sensitivity detectors like mass have significantly reduced many of the above-mentioned shortcomings. This paper provides an overview of the current advances in online two-dimensional-based cell membrane chromatography for screening target components from traditional Chinese medicines with particular emphasis on the instrumentation, preparation of cell membrane stationary phase, advantages, and disadvantages compared to alternative approaches. The last section of the review summarizes the applications of the online two-dimensional high-performance liquid chromatography based cell membrane chromatography reported since its emergence to date (2010-June 2016). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Radioactivity monitor for high-performance liquid chromatography

    International Nuclear Information System (INIS)

    Reeve, D.R.; Crozier, A.

    1977-01-01

    The coupling of a homogeneous radioactivity monitor to a liquid chromatograph involves compromises between the sensitivity of the monitor and the resolution and speed of analysis of the chromatograph. The theoretical relationships between these parameters are considered and expressions derived which make it possible to calculate suitable monitor operating conditions for most types of high-performance liquid chromatography

  15. Polarity-based fractionation in proteomics: hydrophilic interaction vs reversed-phase liquid chromatography.

    Science.gov (United States)

    Jafari, M; Mirzaie, M; Khodabandeh, M; Rezadoost, H; Ghassempour, A; Aboul-Enein, H Y

    2016-07-01

    During recent decades, hydrophilic interaction liquid chromatography (HILIC) ahs been introduced to fractionate or purify especially polar solutes such as peptides and proteins while reversed-phase liquid chromatography (RPLC) is also a common strategy. RPLC is also a common dimension in multidimensional chromatography. In this study, the potential of HILIC vs RPLC chromatography was compared for proteome mapping of human peripheral blood mononuclear cell extract. In HILIC a silica-based stationary phase and for RPLC a C18 column were applied. Then separated proteins were eluted to an ion trap mass spectrometry system. Our results showed that the HILIC leads to more proteins being identified in comparison to RPLC. Among the total 181 identified proteins, 56 and 38 proteins were fractionated specifically by HILIC and RPLC, respectively. In order to demonstrate this, the physicochemical properties of identified proteins such as polarity and hydrophobicity were considered. This analysis indicated that polarity may play a major role in the HILIC separation of proteins vs RPLC. Using gene ontology enrichment analysis, it was also observed that differences in physicochemical properties conform to the cellular compartment and biological features. Finally, this study highlighted the potential of HILIC and the great orthogonality of RPLC in gel-free proteomic studies. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  16. Chirality under confinement - multidimensional constraints in liquid crystalline materials

    NARCIS (Netherlands)

    Sleczkowski, P.B.

    2014-01-01

    The first part of the thesis is devoted to studies of the self-assembled monolayers of discotic liquid crystals by the STM measurements at the liquid/solid interface. For the case of a model H5T molecule the self-assembled monolayers have evidenced both: point and organizational types of chirality,

  17. Ultra-high Performance Liquid Chromatography in Steroid Analysis

    OpenAIRE

    Salonen, Fanny

    2017-01-01

    The latest version of liquid chromatography is ultra-high performance (or pressure) chromatography (UHPLC). In the technique, short and narrow-bore columns with particle sizes below 3 µm are used. The extremely high pressure used results in very short analysis times, excellent separation, and good resolution. This makes UHPLC a good choice for steroidal analysis. Steroids are a highly interesting area of study; they can be recognized as biomarkers for several diseases and are a relevant topic...

  18. Fractionation of fecal neutral steroids by high performance liquid chromatography

    International Nuclear Information System (INIS)

    Jackson, E.M.; Kloss, C.A.; Weintraub, S.T.; Mott, G.E.

    1985-01-01

    Fecal neutral steroids were fractionated by high performance liquid chromatography (HPLC) into three major fractions: 5 beta-H, 3-keto steroids; 5 beta-H, 3 beta-hydroxy steroids; and 5 alpha-H and delta 5-3 beta-hydroxy steroids. This separation was achieved in about 10 minutes, with greater than 97% recovery of standards in each fraction. Gas-liquid chromatographic quantitation of fecal steroids fractionated by either HPLC or thin-layer chromatography gave nearly identical results. A method using both C18 reverse phase and silica HPLC to purify radiolabeled sterols is also described

  19. Development and Validation of Liquid Chromatography- Mass ...

    African Journals Online (AJOL)

    HP

    Method: A novel liquid chromatography–tandem mass spectrometry method for the quantitative determination of naproxen in human K2-EDTA plasma in negative ion mode was employed ..... Practice and Applications of Bio-analytical Method.

  20. Liquid Chromatography Applied to Space System

    Science.gov (United States)

    Poinot, Pauline; Chazalnoel, Pascale; Geffroy, Claude; Sternberg, Robert; Carbonnier, Benjamin

    Searching for signs of past or present life in our Solar System is a real challenge that stirs up the curiosity of scientists. Until now, in situ instrumentation was designed to detect and determine concentrations of a wide number of organic biomarkers. The relevant method which was and still is employed in missions dedicated to the quest of life (from Viking to ExoMars) corresponds to the pyrolysis-GC-MS. Along the missions, this approach has been significantly improved in terms of extraction efficiency and detection with the use of chemical derivative agents (e.g. MTBSTFA, DMF-DMA, TMAH…), and in terms of analysis sensitivity and resolution with the development of in situ high-resolution mass spectrometer (e.g. TOF-MS). Thanks to such an approach, organic compounds such as amino acids, sugars, tholins or polycyclic aromatic hydrocarbons (PAHs) were expected to be found. However, while there’s a consensus that the GC-MS of Viking, Huygens, MSL and MOMA space missions worked the way they had been designed to, pyrolysis is much more in debate (Glavin et al. 2001; Navarro-González et al. 2006). Indeed, (1) it is thought to remove low levels of organics, (2) water and CO2 could interfere with the detection of likely organic pyrolysis products, and (3) only low to mid-molecular weight organic molecules can be detected by this technique. As a result, researchers are now focusing on other in situ techniques which are no longer based on the volatility of the organic matter, but on the liquid phase extraction and analysis. In this line, micro-fluidic systems involving sandwich and/or competitive immunoassays (e.g. LMC, SOLID; Parro et al. 2005; Sims et al. 2012), micro-chip capillary electrophoreses (e.g. MOA; Bada et al. 2008), or nanopore-based analysis (e.g. BOLD; Schulze-Makuch et al. 2012) have been conceived for in situ analysis. Thanks to such approaches, molecular biological polymers (polysaccharides, polypeptides, polynucleotides, phospholipids, glycolipids

  1. Liquid chromatography and liquid chromatography-mass spectrometry analysis of donepezil degradation products

    Directory of Open Access Journals (Sweden)

    Mladenović Aleksandar R.

    2015-01-01

    Full Text Available This study describes the investigation of degradation products of donepezil (DP using stability indicating RP-HPLC method for determination of donepezil, which is a centrally acting reversible acetylcholinesterase inhibitor. In order to investigate the stability of drug and formed degradation products, a forced degradation study of drug sample and finished product under different forced degradation conditions has been conducted. Donepezil hydrochloride and donepezil tablets were subjected to stress degradation conditions recommended by International Conference on Harmonization (ICH. Donepezil hydrochloride solutions were subjected to acid and alkali hydrolysis, chemical oxidation and thermal degradation. Significant degradation was observed under alkali hydrolysis and oxidative degradation conditions. Additional degradation products were observed under the conditions of oxidative degradation. The degradation products observed during forced degradation studies were monitored using the high performance liquid chromatography (HPLC method developed. The parent method was modified in order to obtain LC-MS compatible method which was used to identify the degradation products from forced degradation samples using high resolution mass spectrometry. The mass spectrum provided the precise mass from which derived molecular formula of drug substance and degradation products formed and proved the specificity of the method unambiguously. [Projekat Ministarstva nauke Republike Srbije, br. 172013

  2. Instrumental liquid chromatography: a practical manual on high-performance liquid chromatographic methods

    National Research Council Canada - National Science Library

    Parris, N. A

    1976-01-01

    Available texts on liquid chromatography have tended to emphasize the developments in the theoretical understanding of the technique and methodology or to list numerous applications, complete with experimental details...

  3. Liquid-adsorption chromatography of metal 8-hydroxyquinolinates

    International Nuclear Information System (INIS)

    Basova, E.M.; Bol'shova, T.A.; Shirshova, T.S.

    1988-01-01

    Using the method of liquid-adsorption chromatography separation of 8-hydroxyquinolinates of Cu, Fe, Ga, In, Al, Ni is realized. Thin-layer chromatography (TLC) is used to define the optimum conditions of separation and highly efficient liquid column chromatography (HELC) - for chelate separation. Applicaton of the same sorbent is a very important condition of transition from TLC to HELC. Solica gel Partisil, mobile phase: benzene - isopropanol mixture, containing 1 x 10 -3 M of 8-hydroxyquinoline, are the optimal conditions for the studied chelates separation. But In and Ga in TLC move together, and in HELC they are partially separated, therefore, for their separation the column selectivity should be improved by selection of mobile phase

  4. Validated High Performance Liquid Chromatography Method for ...

    African Journals Online (AJOL)

    Purpose: To develop a simple, rapid and sensitive high performance liquid ... response, tailing factor and resolution of six replicate injections was < 3 %. ... Cefadroxil monohydrate, Human plasma, Pharmacokinetics Bioequivalence ... Drug-free plasma was obtained from the local .... Influence of probenicid on the renal.

  5. Determination of Caffeine in Beverages by High Performance Liquid Chromatography.

    Science.gov (United States)

    DiNunzio, James E.

    1985-01-01

    Describes the equipment, procedures, and results for the determination of caffeine in beverages by high performance liquid chromatography. The method is simple, fast, accurate, and, because sample preparation is minimal, it is well suited for use in a teaching laboratory. (JN)

  6. Beta-induced fluorescence detection in liquid chromatography

    International Nuclear Information System (INIS)

    Malcolme-Lawes, D.J.; Massey, S.; Warwick, P.

    1981-01-01

    A theoretical analysis of beta-induced fluorescence is used to determine the factors which influence the sensitivity of the technique as applied to liquid chromatography. Equations are presented for detector response and for signal-to-noise ratios and the theoretical response for a typical detector is compared with experimentally determined values. (author)

  7. Mallow carotenoids determined by high-performance liquid chromatography

    Science.gov (United States)

    Mallow (corchorus olitorius) is a green vegetable, which is widely consumed either fresh or dry by Middle East population. This study was carried out to determine the contents of major carotenoids quantitatively in mallow, by using a High Performance Liquid Chromatography (HPLC) equipped with a Bis...

  8. High-Performance Liquid Chromatography-Mass Spectrometry.

    Science.gov (United States)

    Vestal, Marvin L.

    1984-01-01

    Reviews techniques for online coupling of high-performance liquid chromatography with mass spectrometry, emphasizing those suitable for application to nonvolatile samples. Also summarizes the present status, strengths, and weaknesses of various techniques and discusses potential applications of recently developed techniques for combined liquid…

  9. Monitoring aged reversed-phase high performance liquid chromatography columns

    NARCIS (Netherlands)

    Bolck, A; Smilde, AK; Bruins, CHP

    1999-01-01

    In this paper, a new approach for the quality assessment of routinely used reversed-phase high performance liquid chromatography columns is presented. A used column is not directly considered deteriorated when changes in retention occur. If attention is paid to the type and magnitude of the changes,

  10. Ultra high performance liquid chromatography of seized drugs

    NARCIS (Netherlands)

    Lurie, I.S.

    2010-01-01

    The primary goal of this thesis is to investigate the use of ultra high performance liquid chromatography (UHPLC) for the analysis of seized drugs. This goal was largely achieved and significant progress was made in achieving improved separation and detection of drugs of forensic interest.

  11. Quantification of Tea Flavonoids by High Performance Liquid Chromatography

    Science.gov (United States)

    Freeman, Jessica D.; Niemeyer, Emily D.

    2008-01-01

    We have developed a laboratory experiment that uses high performance liquid chromatography (HPLC) to quantify flavonoid levels in a variety of commercial teas. Specifically, this experiment analyzes a group of flavonoids known as catechins, plant-derived polyphenolic compounds commonly found in many foods and beverages, including green and black…

  12. Characterization of porous silicon integrated in liquid chromatography chips

    NARCIS (Netherlands)

    Tiggelaar, Roald M.; Verdoold, Vincent; Eghbali, H.; Desmet, G.; Gardeniers, Johannes G.E.

    2009-01-01

    Properties of porous silicon which are relevant for use of the material as a stationary phase in liquid chromatography chips, like porosity, pore size and specific surface area, were determined with high-resolution SEM and N2 adsorption–desorption isotherms. For the anodization conditions

  13. 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

  14. Ionic Liquid-Liquid Chromatography: A New General Purpose Separation Methodology

    OpenAIRE

    Brown, Leslie; Earle, Martyn J; Gilea, Manuela; Plechkova, Natalia V; Seddon, Kenneth R

    2017-01-01

    Ionic liquids can form biphasic solvent systems with many organic solvents and water, and these solvent systems can be used in liquid-liquid separations and countercurrent chromatography. The wide range of ionic liquids that can by synthesised, with specifically tailored properties, represents a new philosophy for the separation of organic, inorganic and bio-based materials. A customised countercurrent chromatograph has been designed and constructed specifically to allow the more viscous char...

  15. Optimizing heterosurface adsorbent synthesis for liquid chromatography

    Science.gov (United States)

    Bogoslovskii, S. Yu.; Serdan, A. A.

    2016-03-01

    The structural and geometric parameters of a silica matrix (SM) for the synthesis of heterosurface adsorbents (HAs) are optimized. Modification is performed by shielding the external surfaces of alkyl-modified silica (AS) using human serum albumin and its subsequent crosslinking. The structural and geometric characteristics of the SM, AS, and HA are measured via low-temperature nitrogen adsorption. It is found that the structural characteristics of AS pores with diameters D 9 nm reduces significantly due to adsorption of albumin. It is concluded that silica gel with a maximum pore size distribution close to 5 nm and a minimal proportion of pores with D > 9 nm is optimal for HA synthesis; this allows us to achieve the greatest similarity between the chromatographic retention parameters for HA and AS. The suitability of the synthesized adsorbents for analyzing drugs in biological fluids through direct sample injection is confirmed by chromatography. It was found that the percentage of the protein fraction detected at the outlet of the chromatographic column is 98%.

  16. Theories to support method development in comprehensive two-dimensional liquid chromatography - A review

    NARCIS (Netherlands)

    Bedani, F.; Schoenmakers, P.J.; Janssen, H.-G.

    2012-01-01

    On-line comprehensive two-dimensional liquid chromatography techniques promise to resolve samples that current one-dimensional liquid chromatography methods cannot adequately deal with. To make full use of the potential of two-dimensional liquid chromatography, optimization is required. Optimization

  17. 21 CFR 862.2250 - Gas liquid chromatography system for clinical use.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Gas liquid chromatography system for clinical use... Instruments § 862.2250 Gas liquid chromatography system for clinical use. (a) Identification. A gas liquid chromatography system for clinical use is a device intended to separate one or more drugs or compounds from a...

  18. 21 CFR 862.2260 - High pressure liquid chromatography system for clinical use.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false High pressure liquid chromatography system for... Clinical Laboratory Instruments § 862.2260 High pressure liquid chromatography system for clinical use. (a) Identification. A high pressure liquid chromatography system for clinical use is a device intended to separate...

  19. Application of genetic algorithms for parameter estimation in liquid chromatography

    International Nuclear Information System (INIS)

    Hernandez Torres, Reynier; Irizar Mesa, Mirtha; Tavares Camara, Leoncio Diogenes

    2012-01-01

    In chromatography, complex inverse problems related to the parameters estimation and process optimization are presented. Metaheuristics methods are known as general purpose approximated algorithms which seek and hopefully find good solutions at a reasonable computational cost. These methods are iterative process to perform a robust search of a solution space. Genetic algorithms are optimization techniques based on the principles of genetics and natural selection. They have demonstrated very good performance as global optimizers in many types of applications, including inverse problems. In this work, the effectiveness of genetic algorithms is investigated to estimate parameters in liquid chromatography

  20. Thin-layer chromatography - liquid chromatography, an ideal supplement demonstrated by the separation of lanthanoids

    International Nuclear Information System (INIS)

    Specker, H.; Hufnagel, A.

    1984-01-01

    All lanthanoids have been separated by thin-layer chromatography (TLC) with short retention times by using a mixture of ether/tetrahydrofurane (THF)/bis-(2-ethylhexyl)-phosphate (HDEHP)/nitric acid. The eluent was empirically tested by synergistic effects. The results have been transferred to high-performance liquid chromatography /HPLC). It was possible to use the same eluent in TLC and HPLC both for the analytical separation of all lanthanoids and for the separation of fission products. The experimental experience gained in HPLC could be applied to the pre-concentration of isotopes in TLC. Both methods excellently supplemented each other in the separation of lanthanoids. (orig.) [de

  1. Ionic Liquid-Liquid Chromatography: A New General Purpose Separation Methodology.

    Science.gov (United States)

    Brown, Leslie; Earle, Martyn J; Gîlea, Manuela A; Plechkova, Natalia V; Seddon, Kenneth R

    2017-08-10

    Ionic liquids can form biphasic solvent systems with many organic solvents and water, and these solvent systems can be used in liquid-liquid separations and countercurrent chromatography. The wide range of ionic liquids that can by synthesised, with specifically tailored properties, represents a new philosophy for the separation of organic, inorganic and bio-based materials. A customised countercurrent chromatograph has been designed and constructed specifically to allow the more viscous character of ionic liquid-based solvent systems to be used in a wide variety of separations (including transition metal salts, arenes, alkenes, alkanes, bio-oils and sugars).

  2. Nano-liquid chromatography applied to enantiomers separation.

    Science.gov (United States)

    Fanali, Salvatore

    2017-02-24

    This paper presents the state of the art concerning the separation of chiral compounds by means of nano-liquid chromatography (nano-LC). The enantiomers' separation and determination are a subject of fundamental importance in various application fields such as pharmaceutical industry, biomedicine, food, agrochemical etc. Nano-LC is a miniaturized chromatographic technique offering some advantages over conventional ones such as low consumption of mobile phase, sample volume and amount of chiral stationary phase, reduced costs etc. This is reported in the first part of the paper illustrating the features of the nano-LC. In addition, chiral resolution methods are briefly illustrated. Some chiral selectors, used in high-performance liquid chromatography have also been applied in nano-LC including cyclodextrins, glycopeptide antibiotics, modified polysaccharides etc. This is discussed in the second part of the review. Finally some examples of the applications available in literature are reported. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Combined high-performance liquid chromatography-radioimmunoassay for cytokinins

    International Nuclear Information System (INIS)

    MacDonald, E.M.S.; Akiyoshi, D.E.; Morris, R.O.

    1981-01-01

    The cytokinins isopentenyladenosine and ribosylzeatin were conjugated to bovine serum albumin and the conjugates used to raise antisera in rabbits. The resulting antisera had high specificity towards the cytokinin haptens and low cross-reactivity towards other purines. They were used as the basis for a radioimmunoassay for cytokinins, which, when applied in conjunction with high-performance liquid chromatography, allowed rapid and sensitive (to the picogram range) estimation and identification of multiple cytokinins from natural plant and bacterial sources. (orig.)

  4. High performance liquid chromatography in studies of radiolabeled antibodies

    International Nuclear Information System (INIS)

    Hnatowich, D.J.

    1986-01-01

    High performance liquid chromatography (HPLC) as applied to the separation of antibodies displays the same advantages as in its other applications, namely good resolution accompanied by fast analysis. It is therefore not surprising that many HPLC columns designed for use with antibodies and other proteins are now available commercially. The properties of proteins which provide the separation are size, hydrophobicity, charge and affinity. The features of each are discussed. (author)

  5. Evolution and Current Trends in Liquid and Supercritical Fluid Chromatography

    OpenAIRE

    Fekete, Szabolcs; Grand-Guillaume-Perrenoud, Alexandre; Guillarme, Davy

    2014-01-01

    The current trend in high performance liquid chromatography (HPLC) tends toward the achievement of higher separation efficiency and shorter analysis time. Indeed, better performance in LC has become increasingly important in recent years mainly driven by the challenges of either analyzing more complex samples or increasing the numbers of samples per time unit. In the recent development of particle technology, the use of fully porous sub-2 m particles and sub-3 m shell particles have received ...

  6. Liquid Chromatography for Analysis of Metformin in Myrmeleon sp.

    OpenAIRE

    Afidatul Muadifah; Hermin Sulistyarti; Sasangka Prasetyawan

    2017-01-01

    Myrmeleon sp is a typical of insect larva which has been used in Indonesia for diabetes treatment. However, there is no sufficient scientific report explaining the bioactive compounds in this insect. Based on our preliminary research, this insect contained metformin, i.e. one of bioactive compounds for the treatment of type-2 diabetes. Therefore, this study is focused on the development of separation technique using high performance liquid chromatography (HPLC) on a reverse phase C-18 column ...

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

    Science.gov (United States)

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

    2017-03-01

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

  8. Comprehensive two-dimensional liquid chromatography and hyphenated liquid chromatography to study the degradation of poly(bisphenol A)carbonate

    NARCIS (Netherlands)

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

    2005-01-01

    Size exclusion chromatography (SEC), gradient polymer elution chromatography (GPEC) and liquid chromatography at critical conditions (LC-CC) have been developed and applied to observe chemical changes in poly(bisphenol A)carbonate (PC) due to hydrolytic degradation. Especially LC-CC appeared to be

  9. Protein separations using enhanced-fluidity liquid chromatography.

    Science.gov (United States)

    Bennett, Raffeal; Olesik, Susan V

    2017-11-10

    Enhanced-fluidity liquid chromatography (EFLC) methods using methanol/H 2 O/CO 2 and hydrophilic interaction liquid chromatography (HILIC) were explored for the separation of proteins and peptides. EFLC is a separation mode that uses a mobile phase made of conventional solvents combined with liquid carbon dioxide (CO 2 ) in subcritical conditions. The addition of liquid CO 2 enhances diffusivity and decreases viscosity while maintaining mixture polarity, which typically results in reduced time of analysis. TFA additive and elevated temperature were leveraged as key factors in the separation of a 13-analyte intact protein mixture in under 5min. Under these conditions EFLC showed modest improvement in terms of peak asymmetry and analysis time over the competing ACN/H 2 O separation. Protein analytes detected by electrospray ionization - quadrupole time of flight, were shown to be unaffected by the addition of CO 2 in the mobile phase. Herein, the feasibility of separating hydrophilic proteins up to 80kDa (with transferrin) is demonstrated for CO 2 -containing mobile phases. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Csaba Horváth and preparative liquid chromatography.

    Science.gov (United States)

    Guiochon, Georges

    2005-06-24

    Few chromatographers have been interested in furthering preparative liquid chromatography. The pioneers, Tswett, Kuhn and Lederer, A.J.P. Martin, Tiselius, isolated fractions but as an intermediate step in the analysis of their samples. The progress in electronics and sensors, and in their miniaturization has lead to the paradoxical situation that the analysts never see the transient pure fractions that their detector quantitates. Yet, over the last 25 years, preparative liquid chromatography has become an important industrial process for the separation, the extraction, and/or the purification of many pharmaceuticals or pharmaceutical intermediates, including pure enantiomers, purified peptides and proteins, compounds that are manufactured at the relatively large industrial scale of a few kilograms to several hundred tons per year. This development that has strongly affected the modem pharmaceutical industry is mainly due to the pioneering work of Csaba Horváth. His work in preparative HPLC was critical at both the practical and the theoretical levels. He was the first scientist in modem times to pay serious attention to the relationships between the curvature of the equilibrium isotherms, the competitive nature of nonlinear isotherms, and the chromatographic band profiles of complex mixtures. The thermodynamics of multi-component phase equilibria and mass transfer kinetics in chromatography attracted his interest and were the focus of ground-breaking contributions. He investigated displacement chromatography, an old method invented by Tiselius that Csaba was first to implement in HPLC. This choice was explained by the essential characteristic of displacement chromatography, in that it delivers fractions that can be far more concentrated than the feed. Remarkably, once the basics of nonlinear chromatography had been mastered in his group, most of the applications that were studied by his coworkers dealt with peptides of various sizes and with proteins. Thus, all

  11. Illicit Drug Analysis Using Two-Dimension Liquid Chromatography/Tandem Mass Spectrometry.

    Science.gov (United States)

    Mallet, Claude; Botch-Jones, Sabra

    2016-10-01

    For the identification of illicit drugs in forensic toxicological casework, analysis can be delayed and potentially compromised due to lengthy sample preparation techniques. For a complete forensic identification, a robust methodology is required and the current trend in forensic laboratories is the use of liquid chromatography coupled to mass spectrometry (LC/MS or LC/MS-MS). However, to achieve satisfactory results, extensive and time-consuming sample preparation protocols are required to reach sub-ng/mL levels. The concept of sequential 2D extraction was designed to capture the retention behavior of a target analyte in response to various extraction parameters. Therefore, optimized conditions can be selected to excise a region of interest during extraction. The utilization of multi-dimensional chromatography combined with a micro-extraction technique was evaluated to decrease sample preparation time while enhancing the separation integrity observed with current single-dimensional chromatography techniques. A wide range of illicit drugs were spiked in human urine and extracted using three extraction protocols for performance evaluation. The extraction process was performed using a reversed-phase solid phase extraction (SPE) in 1D, 2D-optimized, 2D-sequential and cumulative elution modes. The chosen 2D chromatography conditions that were used in this application were identified using a 6 × 6 automated methods development protocol (144 methods total). The extraction of urine samples containing target analytes was completed in less than 20 min. The analysis was performed using 200 µL of the final organic solvent (MeOH) extracts. The limit of detection for all drugs was measured at 100 pg/mL (ppt) from a 1 mL sample volume. Several analytes showed excellent signal at 10 pg/mL (ppt). © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  12. Nanomaterials as stationary phases and supports in liquid chromatography.

    Science.gov (United States)

    Beeram, Sandya R; Rodriguez, Elliott; Doddavenkatanna, Suresh; Li, Zhao; Pekarek, Allegra; Peev, Darin; Goerl, Kathryn; Trovato, Gianfranco; Hofmann, Tino; Hage, David S

    2017-10-01

    The development of various nanomaterials over the last few decades has led to many applications for these materials in liquid chromatography (LC). This review will look at the types of nanomaterials that have been incorporated into LC systems and the applications that have been explored for such systems. A number of carbon-based nanomaterials and inorganic nanomaterials have been considered for use in LC, ranging from carbon nanotubes, fullerenes and nanodiamonds to metal nanoparticles and nanostructures based on silica, alumina, zirconia and titanium dioxide. Many ways have been described for incorporating these nanomaterials into LC systems. These methods have included covalent immobilization, adsorption, entrapment, and the synthesis or direct development of nanomaterials as part of a chromatographic support. Nanomaterials have been used in many types of LC. These applications have included the reversed-phase, normal-phase, ion-exchange, and affinity modes of LC, as well as related methods such as chiral separations, ion-pair chromatography and hydrophilic interaction liquid chromatography. Both small and large analytes (e.g., dyes, drugs, amino acids, peptides and proteins) have been used to evaluate possible applications for these nanomaterial-based methods. The use of nanomaterials in columns, capillaries and planar chromatography has been considered as part of these efforts. Potential advantages of nanomaterials in these applications have included their good chemical and physical stabilities, the variety of interactions many nanomaterials can have with analytes, and their unique retention properties in some separation formats. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Analysis of radioactive mixed hazardous waste using derivatization gas chromatography/mass spectrometry, liquid chromatography, and liquid chromatography/mass spectrometry

    International Nuclear Information System (INIS)

    Campbell, J.A.; Lerner, B.D.; Bean, R.M.; Grant, K.E.; Lucke, R.B.; Mong, G.M.; Clauss, S.A.

    1994-08-01

    Six samples of core segments from Tank 101-SY were analyzed for chelators, chelator fragments, and several carboxylic acids by derivatization gas chromatography/mass spectrometry. The major components detected were ethylenediaminetetraacetic acid, nitroso-iminodiacetic acid, nitrilotriacetic acid, citric acid, succinic acid, and ethylenediaminetriacetic acid. The chelator of highest concentration was ethylenediaminetetraacetic acid in all six samples analyzed. Liquid chromatography was used to quantitate low molecular weight acids including oxalic, formic, glycolic, and acetic acids, which are present in the waste as acid salts. From 23 to 61% of the total organic carbon in the samples analyzed was accounted for by these acids

  14. Comprehensive sample analysis using high performance liquid chromatography with multi-detection

    International Nuclear Information System (INIS)

    Pravadali, Sercan; Bassanese, Danielle N.; Conlan, Xavier A.; Francis, Paul S.; Smith, Zoe M.; Terry, Jessica M.; Shalliker, R. Andrew

    2013-01-01

    Graphical abstract: -- Highlights: •Detection selectivity was assessed with 6 detection modes. •Natural samples show great diversity in detection selectivity. •Complex samples require evaluation using a multifaceted approach to detection. •23/30 known compounds (detected by MS) detected by chemiluminescence, DPPH and UV. -- Abstract: Herein we assess the separation space offered by a liquid chromatography system with an optimised uni-dimensional separation for the determination of the key chemical entities in the highly complex matrix of a tobacco leaf extract. Multiple modes of detection, including UV–visible absorbance, chemiluminescence (acidic potassium permanganate, manganese(IV), and tris(2,2′-bipyridine)ruthenium(III)), mass spectrometry and DPPH radical scavenging were used in an attempt to systematically reduce the data complexity of the sample whilst obtaining a greater degree of molecule-specific information. A large amount of chemical data was obtained, but several limitations in the ability to assign detector responses to particular compounds, even with the aid of complementary detection systems, were observed. Thirty-three compounds were detected via MS on the tobacco extract and 12 out of 32 compounds gave a peak height ratio (PHR) greater than 0.33 on one or more detectors. This paper serves as a case study of these limitations, illustrating why multidimensional chromatography is an important consideration when developing a comprehensive chemical detection system

  15. Comprehensive sample analysis using high performance liquid chromatography with multi-detection.

    Science.gov (United States)

    Pravadali, Sercan; Bassanese, Danielle N; Conlan, Xavier A; Francis, Paul S; Smith, Zoe M; Terry, Jessica M; Shalliker, R Andrew

    2013-11-25

    Herein we assess the separation space offered by a liquid chromatography system with an optimised uni-dimensional separation for the determination of the key chemical entities in the highly complex matrix of a tobacco leaf extract. Multiple modes of detection, including UV-visible absorbance, chemiluminescence (acidic potassium permanganate, manganese(IV), and tris(2,2'-bipyridine)ruthenium(III)), mass spectrometry and DPPH radical scavenging were used in an attempt to systematically reduce the data complexity of the sample whilst obtaining a greater degree of molecule-specific information. A large amount of chemical data was obtained, but several limitations in the ability to assign detector responses to particular compounds, even with the aid of complementary detection systems, were observed. Thirty-three compounds were detected via MS on the tobacco extract and 12 out of 32 compounds gave a peak height ratio (PHR) greater than 0.33 on one or more detectors. This paper serves as a case study of these limitations, illustrating why multidimensional chromatography is an important consideration when developing a comprehensive chemical detection system. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Comprehensive sample analysis using high performance liquid chromatography with multi-detection

    Energy Technology Data Exchange (ETDEWEB)

    Pravadali, Sercan [Australian Centre for Research on Separation Sciences (ACROSS), School of Science and Health, University of Western Sydney (Parramatta), NSW 1797 (Australia); Bassanese, Danielle N.; Conlan, Xavier A.; Francis, Paul S.; Smith, Zoe M.; Terry, Jessica M. [Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences, Deakin University, Victoria 3216 (Australia); Shalliker, R. Andrew, E-mail: R.Shalliker@uws.edu.au [Australian Centre for Research on Separation Sciences (ACROSS), School of Science and Health, University of Western Sydney (Parramatta), NSW 1797 (Australia)

    2013-11-25

    Graphical abstract: -- Highlights: •Detection selectivity was assessed with 6 detection modes. •Natural samples show great diversity in detection selectivity. •Complex samples require evaluation using a multifaceted approach to detection. •23/30 known compounds (detected by MS) detected by chemiluminescence, DPPH and UV. -- Abstract: Herein we assess the separation space offered by a liquid chromatography system with an optimised uni-dimensional separation for the determination of the key chemical entities in the highly complex matrix of a tobacco leaf extract. Multiple modes of detection, including UV–visible absorbance, chemiluminescence (acidic potassium permanganate, manganese(IV), and tris(2,2′-bipyridine)ruthenium(III)), mass spectrometry and DPPH radical scavenging were used in an attempt to systematically reduce the data complexity of the sample whilst obtaining a greater degree of molecule-specific information. A large amount of chemical data was obtained, but several limitations in the ability to assign detector responses to particular compounds, even with the aid of complementary detection systems, were observed. Thirty-three compounds were detected via MS on the tobacco extract and 12 out of 32 compounds gave a peak height ratio (PHR) greater than 0.33 on one or more detectors. This paper serves as a case study of these limitations, illustrating why multidimensional chromatography is an important consideration when developing a comprehensive chemical detection system.

  17. Determination of trimethyllead reference material using high performance liquid chromatography-inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Lu Hai; Wei Chao; Wang Jun; Chao Jingbo; Zhou Tao; Chen Dazhou

    2005-01-01

    A high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICPMS) was combined, and the chromatography conditions were optimized. The stability and homogeneity of a trimethyllead reference material were determined using this method. (authors)

  18. The high pressure electronic control system in liquid chromatography

    International Nuclear Information System (INIS)

    Popescu, Stefan; Popeneciu, Gabriel; Toadere, Florin

    2002-01-01

    The Liquid Chromatography system can perform a wide variety of measurements and separations especially for the organic liquids, with maximum applications flexibility for less than half price of Gas Chromatography. The repeatability and accuracy of results in quantitative high pressure liquid chromatography are highly dependent on the reproducibility and accuracy of both integrated flow rate and mobile phase composition. Flow rate fluctuation leads to poor reproducibility in both integrated peak areas and retention times. Similarly, poor control of mobile phase composition will cause poor repeatability of retention time and peak heights. The our Solvent Delivery System SDS 200 is a single pump system which provides precise compensated flow rates from 0.01 to 10 mL/min, selectable upper pressure limits of 0 to 100 bar or 10 to 450 bar, and solvent compressibility correction. Ternary solvent system on-line mixing capability saves time, reduces solvent waste and provides more flexibility for difficult separations. The pump itself has two different displacement pistons which are used alternately on both suction and discharge, so that intake of the solvent are synchronous. The evacuated solvent from the two pump's chambers is mixed in the reference unit and then is supplied to the damping unit for flow ripple reduction. The SDS Electronic Module ensures the functions: controls the programmed flow rate, detects and shows the solvent pressure in solvent, supplies the step motor, measures and limits the solvent pressure. The control panel of SDS 200, contains a two-stages flow decimal programmer, a eight-positions knob for upper pressure limits, an alarm LED and a parallel port for connection to a PC system. (authors)

  19. VIII All-Russian symposium on molecular liquid chromatography and capillary electrophoresis. Program. Summary of reports

    International Nuclear Information System (INIS)

    2001-01-01

    Program and summary of reports of the VIII All-Russian symposium on molecular liquid chromatography and capillary electrophoresis are performed. The meeting took place 15-19 October, 2001 in Moscow. Many problems of liquid and ion exchange chromatography, capillary electrophoresis, thin-layer chromatography have been discussed extensively. Reports covering properties of sorbents and devices for chromatography are incorporated in the collection [ru

  20. Hydrazine Determination in Sludge Samples by High Performance Liquid Chromatography

    Energy Technology Data Exchange (ETDEWEB)

    G. Elias; G. A. Park

    2006-02-01

    A high-performance liquid chromatographic method using ultraviolet (UV) detection was developed to detect and quantify hydrazine in a variety of environmental matrices. The method was developed primarily for sludge samples, but it is also applicable to soil and water samples. The hydrazine in the matrices was derivatized to their hydrazones with benzaldehyde. The derivatized hydrazones were separated using high performance liquid chromatography (HPLC) with a reversed-phase C-18 column in an isocratic mode with methanol-water (95:5, v/v), and detected with UV detection at 313 nm. The detection limit (25 ml) for the new analytical method is 0.0067 mg ml-1of hydrazine. Hydrazine showed low recovery in soil samples because components in soil oxidized hydrazine. Sludge samples that contained relatively high soil content also showed lower recovery. The technique is relatively simple and cost-effective, and is applicable for hydrazine analysis in different environmental matrices.

  1. Analysis of penicillin G in milk by liquid chromatography.

    Science.gov (United States)

    Boison, J O; Keng, L J; MacNeil, J D

    1994-01-01

    A liquid chromatographic (LC) method that was previously developed for penicillin G residues in animal tissues has been adapted to milk and milk products. After protein precipitation with sodium tungstate, samples are applied to a C18 solid-phase extraction cartridge, from which penicillin is eluted, derivatized with 1,2,4-triazole-mercuric chloride solution, and analyzed by isocratic liquid chromatography (LC) on a C18 column with UV detection at 325 nm. Quantitation is done with reference to penicillin V as an internal standard. Penicillin G recoveries were determined to be > 70% on standards fortified at 3-60 ppb. Accuracy approached 100% using the penicillin V internal standard. The detection limit for penicillin G residues was 3 ppb in fluid milk. Samples may be confirmed by thermospray/LC at concentrations approaching the detection limit of the UV method.

  2. Free silanols and ionic liquids as their suppressors in liquid chromatography.

    Science.gov (United States)

    Buszewska-Forajta, Magdalena; Markuszewski, Michał J; Kaliszan, Roman

    2018-07-20

    In this review, we will firstly discuss the types and the general properties of silica, focusing on the silica support used in chromatography and capillary electrophoresis. Additionally, the characterization of functional groups (silanols and siloxanes) will be considered in terms of activity of the stationary phases. We will then discuss physical chemistry of the stationary phases applied in liquid chromatography and capillary electrophoresis. The use of ionic liquids as a silanols' suppressors will be presented in the next parts of the study, along with the examples of specific applications. The review is completed with conclusions and an outlook for the future developments in the area of analytical applications of ionic liquids. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Fiber-based monolithic columns for liquid chromatography.

    Science.gov (United States)

    Ladisch, Michael; Zhang, Leyu

    2016-10-01

    Fiber-based monoliths for use in liquid chromatographic separations are defined by columns packed with aligned fibers, woven matrices, or contiguous fiber structures capable of achieving rapid separations of proteins, macromolecules, and low molecular weight components. A common denominator and motivating driver for this approach, first initiated 25 years ago, was reducing the cost of bioseparations in a manner that also reduced residence time of retained components while achieving a high ratio of mass to momentum transfer. This type of medium, when packed into a liquid chromatography column, minimized the fraction of stagnant liquid and resulted in a constant plate height for non-adsorbing species. The uncoupling of dispersion from eluent flow rate enabled the surface chemistry of the stationary phase to be considered separately from fluid transport phenomena and pointed to new ways to apply chemistry for the engineering of rapid bioseparations. This paper addresses developments and current research on fiber-based monoliths and explains how the various forms of this type of chromatographic stationary phase have potential to provide new tools for analytical and preparative scale separations. The different stationary phases are discussed, and a model that captures the observed constant plate height as a function of mobile phase velocity is reviewed. Methods that enable hydrodynamically stable fiber columns to be packed and operated over a range of mobile phase flow rates, together with the development of new fiber chemistries, are shown to provide columns that extend the versatility of liquid chromatography using monoliths, particularly at the preparative scale. Graphical Abstract Schematic representation of a sample mixture being separated by a rolled-stationary phase column, resulting separated peaks shown in the chromatogram.

  4. Design of a compressed air modulator to be used in comprehensive multidimensional gas chromatography and its application in the determination of pesticide residues in grapes

    NARCIS (Netherlands)

    Pizzutti, I.R.; Vreuls, J.J.; Kok, A; Roehrs, R.; Martel, S.; Friggi, C.A.; Zanella, R.

    2009-01-01

    In this study, a new modulator that is simple, robust and presents low operation costs, was developed. This modulator uses compressed air to cool two small portions in the first centimeters of the second chromatographic column of a comprehensive multidimensional gas chromatography (GC × GC) system.

  5. Comparison of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography for the separation of synthetic cathinones.

    Science.gov (United States)

    Carnes, Stephanie; O'Brien, Stacey; Szewczak, Angelica; Tremeau-Cayel, Lauriane; Rowe, Walter F; McCord, Bruce; Lurie, Ira S

    2017-09-01

    A comparison of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography for the separation of synthetic cathinones has been conducted. Nine different mixtures of bath salts were analyzed in this study. The three different chromatographic techniques were examined using a general set of controlled synthetic cathinones as well as a variety of other synthetic cathinones that exist as positional isomers. Overall 35 different synthetic cathinones were analyzed. A variety of column types and chromatographic modes were examined for developing each separation. For the ultra high performance supercritical fluid chromatography separations, analyses were performed using a series of Torus and Trefoil columns with either ammonium formate or ammonium hydroxide as additives, and methanol, ethanol or isopropanol organic solvents as modifiers. Ultra high performance liquid chromatographic separations were performed in both reversed phase and hydrophilic interaction chromatographic modes using SPP C18 and SPP HILIC columns. Gas chromatography separations were performed using an Elite-5MS capillary column. The orthogonality of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography was examined using principal component analysis. For the best overall separation of synthetic cathinones, the use of ultra high performance supercritical fluid chromatography in combination with gas chromatography is recommended. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Determination of pertechnetate by liquid chromatography with reductive electrochemical detection

    International Nuclear Information System (INIS)

    Lewis, J.Y.; Zodda, J.P.; Deutsch, E.; Heineman, W.R.

    1983-01-01

    A method utilizing liquid chromatography with electrochemical detection has been developed for the determination of total TcO 4 - (/sup 99m/TcO 4 - and /sup 99m/TcO 4 - ) in 99 Mo//sup 99m/Tc generator eluents. Pertechnetate, which is the starting material for the preparation of many diagnostic radiopharmaceuticals, is generally present in these eluents in the concentration range of 5 X 10 -8 M to 5 X 10 -6 M. No sample pretreatment is necessary since impurities and other components are separated by the high-pressure liquid chromatography (HPLC) NH 2 -bonded column. By use of both static mercury drop (SMDE) and solid electrode detectors, in conjuction with rigorous deoxygenation procedures, total TcO 4 - in generator eluents is readily determined. A severe electrode fouling phenomenon limits the use of solid electrode detectors to TcO 4 - concentrations less than 10 -7 M, the working range for a carbon electrode being 8.5 X 10 -9 to 1.0 X 10 -7 M. The working range for the SMDE is 2.1 X 10 -8 to 1.0 X 10 -4 M TcO 4 -

  7. Description of Adsorption in Liquid Chromatography under Nonideal Conditions.

    Science.gov (United States)

    Ortner, Franziska; Ruppli, Chantal; Mazzotti, Marco

    2018-05-15

    A thermodynamically consistent description of binary adsorption in reversed-phase chromatography is presented, accounting for thermodynamic nonidealities in the liquid and adsorbed phases. The investigated system involves the adsorbent Zorbax 300SB-C18, as well as phenetole and 4- tert-butylphenol as solutes and methanol and water as inert components forming the eluent. The description is based on adsorption isotherms, which are a function of the liquid-phase activities, to account for nonidealities in the liquid phase. Liquid-phase activities are calculated with a UNIQUAC model established in this work, based on experimental phase equilibrium data. The binary interaction in the adsorbed phase is described by the adsorbed solution theory, assuming an ideal (ideal adsorbed solution theory) or real (real adsorbed solution theory) adsorbed phase. Implementation of the established adsorption model in a chromatographic code achieves a quantitative description of experimental elution profiles, with feed compositions exploiting the entire miscible region, and involving a broad range of different eluent compositions (methanol/water). The quantitative agreement of the model and experimental data serves as a confirmation of the underlying physical (thermodynamic) concepts and of their applicability to a broad range of operating conditions.

  8. Purification of flavonoids from licorice using an off-line preparative two-dimensional normal-phase liquid chromatography/reversed-phase liquid chromatography method.

    Science.gov (United States)

    Fan, Yunpeng; Fu, Yanhui; Fu, Qing; Cai, Jianfeng; Xin, Huaxia; Dai, Mei; Jin, Yu

    2016-07-01

    An orthogonal (71.9%) off-line preparative two-dimensional normal-phase liquid chromatography/reversed-phase liquid chromatography method coupled with effective sample pretreatment was developed for separation and purification of flavonoids from licorice. Most of the nonflavonoids were firstly removed using a self-made Click TE-Cys (60 μm) solid-phase extraction. In the first dimension, an industrial grade preparative chromatography was employed to purify the crude flavonoids. Click TE-Cys (10 μm) was selected as the stationary phase that provided an excellent separation with high reproducibility. Ethyl acetate/ethanol was selected as the mobile phase owing to their excellent solubility for flavonoids. Flavonoids co-eluted in the first dimension were selected for further purification using reversed-phase liquid chromatography. Multiple compounds could be isolated from one normal-phase fraction and some compounds with bad resolution in one-dimensional liquid chromatography could be prepared in this two-dimensional system owing to the orthogonal separation. Moreover, this two-dimensional liquid chromatography method was beneficial for the preparation of relatively trace flavonoid compounds, which were enriched in the first dimension and further purified in the second dimension. Totally, 24 flavonoid compounds with high purity were obtained. The results demonstrated that the off-line two-dimensional liquid chromatography method was effective for the preparative separation and purification of flavonoids from licorice. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Evaluation between ultrahigh pressure liquid chromatography and high-performance liquid chromatography analytical methods for characterizing natural dyestuffs.

    Science.gov (United States)

    Serrano, Ana; van Bommel, Maarten; Hallett, Jessica

    2013-11-29

    An evaluation was undertaken of ultrahigh pressure liquid chromatography (UHPLC) in comparison to high-performance liquid chromatography (HPLC) for characterizing natural dyes in cultural heritage objects. A new UHPLC method was optimized by testing several analytical parameters adapted from prior UHPLC studies developed in diverse fields of research. Different gradient elution programs were tested on seven UHPLC columns with different dimensions and stationary phase compositions by applying several mobile phases, flow rates, temperatures, and runtimes. The UHPLC method successfully provided more improved data than that achieved by the HPLC method. Indeed, even though carminic acid has shown circa 146% higher resolution with HPLC, UHPLC resulted in an increase of 41-61% resolution and a decrease of 91-422% limit of detection, depending on the dye compound. The optimized method was subsequently assigned to analyse 59 natural reference materials, in which 85 different components were ascribed with different physicochemical properties, in order to create a spectral database for future characterization of dyes in cultural heritage objects. The majority of these reference samples could be successfully distinguished with one single method through the examination of these compounds' retention times and their spectra acquired with a photodiode array detector. These results demonstrate that UHPLC analyses are extremely valuable for the acquisition of more precise chromatographic information concerning natural dyes with complex mixtures of different and/or closely related physicochemical properties, essential for distinguishing similar species of plants and animals used to colour cultural heritage objects. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Method transfer from high-pressure liquid chromatography to ultra-high-pressure liquid chromatography. II. Temperature and pressure effects.

    Science.gov (United States)

    Åsberg, Dennis; Samuelsson, Jörgen; Leśko, Marek; Cavazzini, Alberto; Kaczmarski, Krzysztof; Fornstedt, Torgny

    2015-07-03

    The importance of the generated temperature and pressure gradients in ultra-high-pressure liquid chromatography (UHPLC) are investigated and compared to high-pressure liquid chromatography (HPLC). The drug Omeprazole, together with three other model compounds (with different chemical characteristics, namely uncharged, positively and negatively charged) were used. Calculations of the complete temperature profile in the column at UHPLC conditions showed, in our experiments, a temperature difference between the inlet and outlet of 16 °C and a difference of 2 °C between the column center and the wall. Through van't Hoff plots, this information was used to single out the decrease in retention factor (k) solely due to the temperature gradient. The uncharged solute was least affected by temperature with a decrease in k of about 5% while for charged solutes the effect was more pronounced, with k decreases up to 14%. A pressure increase of 500 bar gave roughly 5% increase in k for the uncharged solute, while omeprazole and the other two charged solutes gave about 25, 20 and 15% increases in k, respectively. The stochastic model of chromatography was applied to estimate the dependence of the average number of adsorption/desorption events (n) and the average time spent by a molecule in the stationary phase (τs) on temperature and pressure on peak shape for the tailing, basic solute. Increasing the temperature yielded an increase in n and decrease in τs which resulted in less skew at high temperatures. With increasing pressure, the stochastic modeling gave interesting results for the basic solute showing that the skew of the peak increased with pressure. The conclusion is that pressure effects are more pronounced for both retention and peak shape than the temperature effects for the polar or charged compounds in our study. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. (Vapour + liquid) equilibria of ternary systems with ionic liquids using headspace gas chromatography

    International Nuclear Information System (INIS)

    Mokhtarani, Babak; Gmehling, Juergen

    2010-01-01

    (Vapour + liquid) equilibrium (VLE) data for the ternary systems (hexane + benzene), (hexane + cyclohexane), (benzene + cyclohexane), and (ethanol + water) with an ionic liquid as entrainer for extractive distillation were measured by headspace gas chromatography. As ionic liquids, 1-hexyl-3-methyl-imidazolium bis (trifluoromethyl-sulfonyl) imide [HMIM][BTI], 1-octyl-3-methyl-imidazolium bis (trifluoromethyl-sulfonyl) imide [OMIM][BTI], 1-octyl-3-methyl-imidazolium trifluoro-methanesulfonate [OMIM][OTF], and 1-butyl-3-methyl-imidazolium trifluoro-methanesulfonate [BMIM][OTF] were used. The experimental data show that the ionic liquids investigated have a great influence on the separation factors of the systems (hexane + benzene), (hexane + cyclohexane), and (benzene + cyclohexane). The experimental data were compared with the predicted results using mod. UNIFAC (Do). The predicted results are in good agreement with the experimental data.

  12. (Vapour + liquid) equilibria of ternary systems with ionic liquids using headspace gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Mokhtarani, Babak [Chemistry and Chemical Engineering Research Center of Iran, P.O. Box 14335-186, Tehran (Iran, Islamic Republic of); Gmehling, Juergen, E-mail: gmehling@tech.chem.uni-oldenburg.d [Carl von Ossietzky Universitaet Oldenburg, Technische Chemie, D-26111 Oldenburg (Germany)

    2010-08-15

    (Vapour + liquid) equilibrium (VLE) data for the ternary systems (hexane + benzene), (hexane + cyclohexane), (benzene + cyclohexane), and (ethanol + water) with an ionic liquid as entrainer for extractive distillation were measured by headspace gas chromatography. As ionic liquids, 1-hexyl-3-methyl-imidazolium bis (trifluoromethyl-sulfonyl) imide [HMIM][BTI], 1-octyl-3-methyl-imidazolium bis (trifluoromethyl-sulfonyl) imide [OMIM][BTI], 1-octyl-3-methyl-imidazolium trifluoro-methanesulfonate [OMIM][OTF], and 1-butyl-3-methyl-imidazolium trifluoro-methanesulfonate [BMIM][OTF] were used. The experimental data show that the ionic liquids investigated have a great influence on the separation factors of the systems (hexane + benzene), (hexane + cyclohexane), and (benzene + cyclohexane). The experimental data were compared with the predicted results using mod. UNIFAC (Do). The predicted results are in good agreement with the experimental data.

  13. Reduction of silanophilic interactions in liquid chromatography with the use of ionic liquids

    International Nuclear Information System (INIS)

    MarszaII, MichaI Piotr; Baczek, Tomasz; Kaliszan, Roman

    2005-01-01

    A suppression of silanophilic interactions by the selected ionic liquids added to the mobile phase in thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) is reported. Acetonitrile was used as the eluent, alone or with various concentrations of water and phosphoric buffer pH 3. Selectivity of the normal (NP) and the reversed (RP) stationary phase material was examined using a series of proton-acceptor basic drugs analytes. The ionic liquids studied appeared to significantly affect analyte retention in NP-TLC, RP-TLC and RP-HPLC systems tested. Consequently, the increased separation selectivity was attained. Due to ionic liquid additives to eluent even analytes could be chromatographed, which were not eluted from the silica-based stationary phase materials with 100% of acetonitrile in the mobile phase. Addition of ionic liquid already in very small concentration (0.5%, v/v) could reduce the amount of acetonitrile used during the optimization of basic analytes separations in TLC and HPLC systems. Moreover, the influence of temperature on the separation of basic analytes was demonstrated and considered in practical HPLC method development

  14. Reduction of silanophilic interactions in liquid chromatography with the use of ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    MarszaII, MichaI Piotr [Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdansk, Gen. J. Hallera 107, 80-416 Gdansk (Poland); Baczek, Tomasz [Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdansk, Gen. J. Hallera 107, 80-416 Gdansk (Poland); Kaliszan, Roman [Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdansk, Gen. J. Hallera 107, 80-416 Gdansk (Poland)]. E-mail: roman.kaliszan@amg.gda.pl

    2005-08-22

    A suppression of silanophilic interactions by the selected ionic liquids added to the mobile phase in thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) is reported. Acetonitrile was used as the eluent, alone or with various concentrations of water and phosphoric buffer pH 3. Selectivity of the normal (NP) and the reversed (RP) stationary phase material was examined using a series of proton-acceptor basic drugs analytes. The ionic liquids studied appeared to significantly affect analyte retention in NP-TLC, RP-TLC and RP-HPLC systems tested. Consequently, the increased separation selectivity was attained. Due to ionic liquid additives to eluent even analytes could be chromatographed, which were not eluted from the silica-based stationary phase materials with 100% of acetonitrile in the mobile phase. Addition of ionic liquid already in very small concentration (0.5%, v/v) could reduce the amount of acetonitrile used during the optimization of basic analytes separations in TLC and HPLC systems. Moreover, the influence of temperature on the separation of basic analytes was demonstrated and considered in practical HPLC method development.

  15. Hydrophilic interaction liquid chromatography in the speciation analysis of selenium.

    Science.gov (United States)

    Sentkowska, Aleksandra; Pyrzynska, Krystyna

    2018-02-01

    The hydrophilic interaction liquid chromatography (HILIC) coupled to mass spectrometry was employed to study retention behavior of selected selenium compounds using two different HILIC stationary phases: silica and zwitterionic. Two organic solvents - acetonitrile and methanol - were compared as a component of mobile phase. Separation parameters such as a content of organic modifier, the eluent pH and inorganic buffer concentration were investigated. Based on all observations, methanol seems to be beneficial for the separation of studied compounds. The optimal HILIC separation method involved silica column and eluent composed of 85% MeOH and CH 3 COONH 4 (8 mM, pH 7) was compared to RP method in terms of time of the single run, the separation efficiency and limit of detection. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Cortisol production rates measured by liquid chromatography/mass spectrometry

    International Nuclear Information System (INIS)

    Esteban, N.V.; Yergey, A.L.

    1990-01-01

    Cortisol production rates (FPRs) in physiologic and pathologic states in humans have been investigated over the past 30 years. However, there has been conflicting evidence concerning the validity of the currently accepted value of FPRs in humans (12 to 15 mg/m2/d) as determined by radiotracer methodology. The present study reviews previous methods proposed for the measurement of FPRs in humans and discusses the applications of the first method for the direct determination of 24-hour plasma FPRs during continuous administration of a stable isotope, using a thermospray high-pressure liquid chromatography-mass spectrometry technique. The technique is fast, sensitive, and, unlike gas chromatography-mass spectrometry methods, does not require derivatization, allowing on-line detection and quantification of plasma cortisol after a simple extraction procedure. The results of determination of plasma FPRs by stable tracer/mass spectrometry are directly in units of mass/time and, unlike radiotracer methods, are independent of any determination of volume of distribution or cortisol concentration. Our methodology offers distinct advantages over radiotracer techniques in simplicity and reliability since only single measurements of isotope ratios are required. The technique was validated in adrenalectomized patients. Circadian variations in daily FRPs were observed in normal volunteers, and, to date, results suggest a lower FRP in normal children and adults than previously believed. 88 references

  17. Modern Aspects Of Fluorometric Detection In Liquid-Phase Chromatography

    Science.gov (United States)

    Bousquet, Bernard; Garnier, Jean P.; Dreux, Claude

    1983-10-01

    Recent advances are described in the combined use of fluorometric derivatization and high performance liquid chromatography (HPLC) for clinical chemistry determinations. Derivatives (especially dansyl derivatives) can be formed prior to chromatography in the case of estrogens, amino acids, and catecholamines. In post-column reactions, we preferred to use air-segmented reactions as they conform better to all the optimized chromatographic and spectrofluorometric parameters. Fluorescent derivatives produced from cate-cholamines, tryptophan and its metabolites, hydroxyindoles, tryptamine, amino acids, sugars, polyamines, and other substances are often sufficiently sensitive to be detected in picogram quantities by HPLC. Their reaction principle and some of their applications to samples are described. Recently, chemical excitation of fluorophore-like dansyl amino acid was proposed as a detection system for HPLC. By a post-column reaction, a fluorophore can be made to emit light by its reaction with trichlorophenyl oxalate (TCPO) and hydrogen peroxide. The detection limit of this system is about 10 fmol for each dansyl amino acid. Application of this new reaction to catecholamines opens up new prospects for fluorometric detection.

  18. Group type analysis of asphalt by column liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, C.; Yang, J.; Xue, Y.; Li, Y. [Chinese Academy of Science, Taiyuan (China)

    2008-07-01

    An improved analysis method for characterization of asphalt was established. The method is based on column chromatography technique. The asphalts were separated into four groups: saturates, aromatics, resins, and asphaltenes, quantitatively. About 0.1 g of sample was required in each analysis. About 20 mL of n-heptanes was used to separate out saturates first. Then about 35 mL of n-heptanes/dichloromethane (.5, v/v) mixture was used to separate out aromatics. About 30 mL of dichloromethane/tetrahydrofuran (1/3, v/v) mixture was used to separate out resin. The quality of the separation was confirmed by infrared spectra (IR) and {sup 1}H NMR analysis. The model compounds, tetracosan for saturates, dibenz(o)anthracen for aromatics, and acetanilide for resins were used for verification. The IR and {sup 1}H NMR analysis of the prepared fractions from the column liquid chromatography were in good agreement that of pure reagents.

  19. Detailed analysis of petroleum cuts by multidimensional gas chromatography; Analyse detaillee de coupes petrolieres par chromatographie en phase gazeuse multidimensionnelle

    Energy Technology Data Exchange (ETDEWEB)

    Vendeuvre, C.

    2006-01-15

    The limitations of petroleum resources implying a better valorisation of crude oil through the optimisation of production, refinery and petrochemistry processes, as well as the environmental regulations have strengthened the necessity of more detailed characterisation of petroleum products. In order to take up this challenge, efficient analytical tools have to be developed. This work demonstrates that comprehensive two-dimensional gas chromatography (GCxGC) constitutes a major advance compared to GC owing to its improved resolution power and to the structured chromatograms indicating the polarity and the volatility of hydrocarbons. The principle of GCxGC is based on the analysis of a whole sample in two independent dimensions of separation achieved using two GC columns of different selectivities; between the two columns a modulator device samples, focuses and re-injects small portions of the effluent from the first column into the second one. Since its introduction in 1991, GCxGC has known a rapid growth and has received a wide acceptance by the analytical science community. The competitive situation has considerably evolved during this thesis with the introduction of commercial systems and the two first sessions of an international symposium dedicated to this technique (Volendam, 2003 and Atlanta, 2004). The key points of the thesis concern the development of a GCxGC prototype system using dual jets CO{sub 2} technology and a data processing program; the evaluation of a retention model allowing a rational choice of operating conditions; and the application of this technique to various and complex issues. Thus, effluents from petrochemistry, refinery or pollution areas have been analysed according to the chemical classes of hydrocarbons and to their number of carbon atoms; a new method for obtaining distillation curves for each chemical group was also presented. Furthermore, the hyphenation of GCxGC with a specific sulphur detector revealed a great interest for

  20. Analytical method for high resolution liquid chromatography for quality control French Macaw

    International Nuclear Information System (INIS)

    Garcia Penna, Caridad M; Torres Amaro, Leonid; Menendez Castillo, Rosa; Sanchez, Esther; Martinez Espinosa, Vivian; Gonzalez, Maria Lidia; Rodriguez, Carlos

    2007-01-01

    Was developed and validated an analytical method for high resolution liquid chromatography applicable to quality control of drugs dry French Macaw (Senna alata L. Roxb.) With ultraviolet detection at 340 nm. The method for high resolution liquid chromatography used to quantify the sennosides A and B, main components, was validated and proved to be specific, linear, precise and accurate. (Author)

  1. Recent advances in ultra-high performance liquid chromatography for the analysis of traditional chinese medicine

    Science.gov (United States)

    Traditional Chinese medicines (TCMs) have been widely used for the prevention and treatment of various diseases for thousands of years in China. Ultra Performance Liquid Chromatography (UHPLC) is a relatively new technique offering new possibilities in liquid chromatography. This paper reviews recen...

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

    Science.gov (United States)

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

    2009-01-01

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

  3. Towards Chip Scale Liquid Chromatography and High Throughput Immunosensing

    Energy Technology Data Exchange (ETDEWEB)

    Ni, Jing [Iowa State Univ., Ames, IA (United States)

    2000-09-21

    This work describes several research projects aimed towards developing new instruments and novel methods for high throughput chemical and biological analysis. Approaches are taken in two directions. The first direction takes advantage of well-established semiconductor fabrication techniques and applies them to miniaturize instruments that are workhorses in analytical laboratories. Specifically, the first part of this work focused on the development of micropumps and microvalves for controlled fluid delivery. The mechanism of these micropumps and microvalves relies on the electrochemically-induced surface tension change at a mercury/electrolyte interface. A miniaturized flow injection analysis device was integrated and flow injection analyses were demonstrated. In the second part of this work, microfluidic chips were also designed, fabricated, and tested. Separations of two fluorescent dyes were demonstrated in microfabricated channels, based on an open-tubular liquid chromatography (OT LC) or an electrochemically-modulated liquid chromatography (EMLC) format. A reduction in instrument size can potentially increase analysis speed, and allow exceedingly small amounts of sample to be analyzed under diverse separation conditions. The second direction explores the surface enhanced Raman spectroscopy (SERS) as a signal transduction method for immunoassay analysis. It takes advantage of the improved detection sensitivity as a result of surface enhancement on colloidal gold, the narrow width of Raman band, and the stability of Raman scattering signals to distinguish several different species simultaneously without exploiting spatially-separated addresses on a biochip. By labeling gold nanoparticles with different Raman reporters in conjunction with different detection antibodies, a simultaneous detection of a dual-analyte immunoassay was demonstrated. Using this scheme for quantitative analysis was also studied and preliminary dose-response curves from an immunoassay of a

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

    Science.gov (United States)

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

    2015-01-01

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

  5. Analysis of short-chain acids from anaerobic bacteria by high-performance liquid chromatography.

    OpenAIRE

    Guerrant, G O; Lambert, M A; Moss, C W

    1982-01-01

    A standard mixture of 25 short-chain fatty acids was resolved by high-performance liquid chromatography, using an Aminex HPX-87 column. The acids produced in culture media by anaerobic bacteria were analyzed by high-performance liquid chromatography after extraction with ether and reextraction into a small volume of 0.1 N NaOH. The presence of fumaric acid in culture extracts of Peptostreptococcus anaerobius was confirmed by gas chromatography-mass spectrometry analysis of the trapped eluent ...

  6. Quantitation of Metformin in Human Plasma and Urine by Hydrophilic Interaction Liquid Chromatography and Application to a Pharmacokinetic Study

    DEFF Research Database (Denmark)

    Nielsen, Flemming; Hougaard Christensen, Mette Marie; Brøsen, Kim

    2014-01-01

    : We describe an analytical method for the quantification of the widely used antihyperglycemic agent, metformin, in human plasma and urine. The separation was performed using isocratic hydrophilic interaction liquid chromatography on a Luna hydrophilic interaction liquid chromatography column (125...

  7. Phytochemical Profile of Erythrina variegata by Using High-Performance Liquid Chromatography and Gas Chromatography-Mass Spectroscopy Analyses

    OpenAIRE

    Suriyavathana Muthukrishnan; Subha Palanisamy; Senthilkumar Subramanian; Sumathi Selvaraj; Kavitha Rani Mari; Ramalingam Kuppulingam

    2016-01-01

    Natural products derived from plant sources have been utilized to treat patients with numerous diseases. The phytochemical constituents present in ethanolic leaf extract of Erythrina variegata (ELEV) were identified by using high-performance liquid chromatography (HPLC) and gas chromatography-mass spectroscopy (GC-MS) analyses. Shade dried leaves were powdered and extracted with ethanol for analyses through HPLC to identify selected flavonoids and through GC-MS to identify other molecules. Th...

  8. Study of Separation and Identification of the Active Ingredients in Gardenia jasminoides Ellis Based on a Two-Dimensional Liquid Chromatography by Coupling Reversed Phase Liquid Chromatography and Hydrophilic Interaction Liquid Chromatography.

    Science.gov (United States)

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

    2017-01-01

    In this paper, by coupling reversed phase liquid chromatography (RPLC) and hydrophilic interaction liquid chromatography (HILIC), a two-dimensional liquid chromatography system was developed for separation and identification of the active ingredients in Gardenia jasminoides Ellis (GJE). By applying the semi-preparative C18 column as the first dimension and the core-shell column as the second dimension, a total of 896 peaks of GJE were separated. Among the 896 peaks, 16 active ingredients including geniposide, gardenoside, gardoside, etc. were identified by mass spectrometry analysis. The results indicated that the proposed two-dimensional RPLC/HILIC system was an effective method for the analysis of GJE and might hold a high potential to become a useful tool for analysis of other complex mixtures. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. Off-line coupling of multidimensional immunoaffinity chromatography and ion mobility spectrometry: A promising partnership.

    Science.gov (United States)

    Armenta, Sergio; de la Guardia, Miguel; Abad-Fuentes, Antonio; Abad-Somovilla, Antonio; Esteve-Turrillas, Francesc A

    2015-12-24

    The extreme specificity of immunoaffinity chromatography (IAC) columns coupled to the high sensitivity of ion mobility spectrometry (IMS) measurements makes this combination really useful for rapid, selective, and sensitive determination of a high variety of analytes in different samples. The capabilities of the IAC-IMS coupling have been highlighted under three different scenarios: (i) multiclass residue analysis using a single IAC column, (ii) multiclass residue analysis using stacked IAC columns, and (iii) isomer analysis. In the first case, the determination of three strobilurin fungicides - azoxystrobin, picoxystrobin, and pyraclostrobin - in water and strawberry juice was considered, obtaining limits of quantification (LOQs) from 11 to 63μgL(-1). Recoveries from 96 to 106% for water, and from 67 to 104% for strawberry juice were obtained. In the second case, anilinopyrimidine compounds, including two analytes with similar drift time, were selectively retained in different IAC columns and analyzed after independent elution in commercial wine samples by IMS. LOQ values of 16, 14 and 12μgL(-1) were obtained for pyrimethanil, mepanipyrim, and cyprodinil, respectively. The obtained recoveries for wine samples spiked with 25 and 100μgL(-1) were from 82 to 123%. Additionally, the stacked IAC columns concept was applied to the separation of Z and E isomers of azoxystrobin that were selectively retained in specific IAC columns and quantified by IMS. Recoveries between 91 and 94% were obtained for both isomers in water samples. Copyright © 2015 Elsevier B.V. All rights reserved.

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

    DEFF Research Database (Denmark)

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

    1994-01-01

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

  11. Unified pH values of liquid chromatography mobile phases.

    Science.gov (United States)

    Suu, Agnes; Jalukse, Lauri; Liigand, Jaanus; Kruve, Anneli; Himmel, Daniel; Krossing, Ingo; Rosés, Martí; Leito, Ivo

    2015-03-03

    This work introduces a conceptually new approach of measuring pH of mixed-solvent liquid chromatography (LC) mobile phases. Mobile phase pH is very important in LC, but its correct measurement is not straightforward, and all commonly used approaches have deficiencies. The new approach is based on the recently introduced unified pH (pH(abs)) scale, which enables direct comparison of acidities of solutions made in different solvents based on chemical potential of the proton in the solutions. This work represents the first experimental realization of the pH(abs) concept using differential potentiometric measurement for comparison of the chemical potentials of the proton in different solutions (connected by a salt bridge), together with earlier published reference points for obtaining the pH(abs) values (referenced to the gas phase) or pH(abs)(H₂O) values (referenced to the aqueous solution). The liquid junction potentials were estimated in the framework of Izutsu's three-component method. pH(abs) values for a number of common LC and LC-MS mobile phases have been determined. The pH(abs) scale enables for the first time direct comparison of acidities of any LC mobile phases, with different organic additives, different buffer components, etc. A possible experimental protocol of putting this new approach into chromatographic practice has been envisaged and its applicability tested. It has been demonstrated that the ionization behavior of bases (cationic acids) in the mobile phases can be better predicted by using the pH(abs)(H₂O) values and aqueous pKa values than by using the alternative means of expressing mobile phase acidity. Description of the ionization behavior of acids on the basis of pH(abs)(H₂O) values is possible if the change of their pKa values with solvent composition change is taken into account.

  12. Liquid chromatography-mass spectrometry in forensic toxicology.

    Science.gov (United States)

    Van Bocxlaer, J F; Clauwaert, K M; Lambert, W E; Deforce, D L; Van den Eeckhout, E G; De Leenheer, A P

    2000-01-01

    Liquid chromatography-mass spectrometry has evolved from a topic of mainly research interest into a routinely usable tool in various application fields. With the advent of new ionization approaches, especially atmospheric pressure, the technique has established itself firmly in many areas of research. Although many applications prove that LC-MS is a valuable complementary analytical tool to GC-MS and has the potential to largely extend the application field of mass spectrometry to hitherto "MS-phobic" molecules, we must recognize that the use of LC-MS in forensic toxicology remains relatively rare. This rarity is all the more surprising because forensic toxicologists find themselves often confronted with the daunting task of actually searching for evidence materials on a scientific basis without any indication of the direction in which to search. Through the years, mass spectrometry, mainly in the GC-MS form, has gained a leading role in the way such quandaries are tackled. The advent of robust, bioanalytically compatible combinations of liquid chromatographic separation with mass spectrometric detection really opens new perspectives in terms of mass spectrometric identification of difficult molecules (e.g., polar metabolites) or biopolymers with toxicological relevance, high throughput, and versatility. Of course, analytical toxicologists are generally mass spectrometry users rather than mass spectrometrists, and this difference certainly explains the slow start of LC-MS in this field. Nevertheless, some valuable applications have been published, and it seems that the introduction of the more universal atmospheric pressure ionization interfaces really has boosted interests. This review presents an overview of what has been realized in forensic toxicological LC-MS. After a short introduction into LC-MS interfacing operational characteristics (or limitations), it covers applications that range from illicit drugs to often abused prescription medicines and some

  13. Microcystin Detection Characteristics of Fluorescence Immunochromatography and High Performance Liquid Chromatography

    International Nuclear Information System (INIS)

    Pyo, Dong Jin; Park, Geun Young; Choi, Jong Chon; Oh, Chang Suk

    2005-01-01

    Different detection characteristics of fluorescence immunochromatography method and high performance liquid chromatography (HPLC) method for the analysis of cyanobacterial toxins were studied. In particular, low and high limits of detection, detection time and reproducibility and detectable microcystin species were compared when fluorescence immunochromatography method and high performance liquid chromatography method were applied for the detection of microcystin (MC), a cyclic peptide toxin of the freshwater cyanobacterium Microcystis aeruginosa. A Fluorescence immunochromatography assay system has the unique advantages of short detection time and low detection limit, and high performance liquid chromatography detection method has the strong advantage of individual quantifications of several species of microcystins

  14. Simultaneous analysis for water- and fat-soluble vitamins by a novel single chromatography technique unifying supercritical fluid chromatography and liquid chromatography.

    Science.gov (United States)

    Taguchi, Kaori; Fukusaki, Eiichiro; Bamba, Takeshi

    2014-10-03

    Chromatography techniques usually use a single state in the mobile phase, such as liquid, gas, or supercritical fluid. Chromatographers manage one of these techniques for their purpose but are sometimes required to use multiple methods, or even worse, multiple techniques when the target compounds have a wide range of chemical properties. To overcome this challenge, we developed a single method covering a diverse compound range by means of a "unified" chromatography which completely bridges supercritical fluid chromatography and liquid chromatography. In our method, the phase state was continuously changed in the following order; supercritical, subcritical and liquid. Moreover, the gradient of the mobile phase starting at almost 100% CO2 was replaced with 100% methanol at the end completely. As a result, this approach achieved further extension of the polarity range of the mobile phase in a single run, and successfully enabled the simultaneous analysis of fat- and water-soluble vitamins with a wide logP range of -2.11 to 10.12. Furthermore, the 17 vitamins were exceptionally separated in 4min. Our results indicated that the use of dense CO2 and the replacement of CO2 by methanol are practical approaches in unified chromatography covering diverse compounds. Additionally, this is a first report to apply the novel approach to unified chromatography, and can open another door for diverse compound analysis in a single chromatographic technique with single injection, single column and single system. Copyright © 2014. Published by Elsevier B.V.

  15. Investigation of Symphytum cordatum alkaloids by liquid-liquid partitioning, thin-layer chromatography and liquid chromatography-ion-trap mass spectrometry

    International Nuclear Information System (INIS)

    Mroczek, Tomasz; Ndjoko-Ioset, Karine; Glowniak, Kazimierz; Mietkiewicz-Capala, Agnieszka; Hostettmann, Kurt

    2006-01-01

    From the alkalised crude extract of Symphytum cordatum (L.) W.K. roots, pyrrolizidine alkaloids (PAs) were extracted as free tertiary bases and polar N-oxides in a merely one-step liquid-liquid partitioning (LLP) in separation funnel and subsequently pre-fractionated by preparative multiple-development (MD) thin-layer chromatography (TLC) on silica gel plates. In this way three alkaloid fractions of different polarities and retention on silica gel plates were obtained as: the most polar N-oxides of the highest retention, the tertiary bases of medium retention, and diesterified N-oxides of the lowest retention. The former fraction was reduced into free bases by sodium hydrosulfite and purified by LLP on Extrelut-NT3 cartridge. It was further analysed together with the two other fractions by high-performance liquid chromatography (HPLC)-ion-trap mass spectrometry with atmospheric pressure chemical ionization (APCI) interface on XTerra C 18 column using a gradient elution. Based on MS n spectra, 18 various alkaloids have been tentatively determined for the first time in this plant as the following types of structure: echimidine-N-oxide (three diasteroisomers), 7-sarracinyl-9-viridiflorylretronecine (two diasteroisomers), echimidine (two diasteroisomers), lycopsamine (two diasteroisomers), dihydroechinatine-N-oxide, dihydroheliospathuline-N-oxide, lycopsamine-N-oxide (three diasteroisomers), 7-acetyllycopsamine-N-oxide, symphytine-N-oxide (two diasteroisomers) and 2'',3''-epoxyechiumine-N-oxide

  16. Investigation of Symphytum cordatum alkaloids by liquid-liquid partitioning, thin-layer chromatography and liquid chromatography-ion-trap mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Mroczek, Tomasz [Department of Pharmacognosy with Medicinal Plants Laboratory, Medical University, 1 Chodzki St., 20-093 Lublin (Poland)]. E-mail: tmroczek@pharmacognosy.org; Ndjoko-Ioset, Karine [Laboratoire de Pharmacognosie et Phytochimie, Ecole de Pharmacie Geneve-Lausanne, Universite de Geneve, Quai Ernest-Ansermet 30, CH-1211 Geneva 4 (Switzerland); Glowniak, Kazimierz [Department of Pharmacognosy with Medicinal Plants Laboratory, Medical University, 1 Chodzki St., 20-093 Lublin (Poland); Mietkiewicz-Capala, Agnieszka [Department of Pharmacognosy with Medicinal Plants Laboratory, Medical University, 1 Chodzki St., 20-093 Lublin (Poland); Hostettmann, Kurt [Laboratoire de Pharmacognosie et Phytochimie, Ecole de Pharmacie Geneve-Lausanne, Universite de Geneve, Quai Ernest-Ansermet 30, CH-1211 Geneva 4 (Switzerland)

    2006-05-04

    From the alkalised crude extract of Symphytum cordatum (L.) W.K. roots, pyrrolizidine alkaloids (PAs) were extracted as free tertiary bases and polar N-oxides in a merely one-step liquid-liquid partitioning (LLP) in separation funnel and subsequently pre-fractionated by preparative multiple-development (MD) thin-layer chromatography (TLC) on silica gel plates. In this way three alkaloid fractions of different polarities and retention on silica gel plates were obtained as: the most polar N-oxides of the highest retention, the tertiary bases of medium retention, and diesterified N-oxides of the lowest retention. The former fraction was reduced into free bases by sodium hydrosulfite and purified by LLP on Extrelut-NT3 cartridge. It was further analysed together with the two other fractions by high-performance liquid chromatography (HPLC)-ion-trap mass spectrometry with atmospheric pressure chemical ionization (APCI) interface on XTerra C{sub 18} column using a gradient elution. Based on MS {sup n} spectra, 18 various alkaloids have been tentatively determined for the first time in this plant as the following types of structure: echimidine-N-oxide (three diasteroisomers), 7-sarracinyl-9-viridiflorylretronecine (two diasteroisomers), echimidine (two diasteroisomers), lycopsamine (two diasteroisomers), dihydroechinatine-N-oxide, dihydroheliospathuline-N-oxide, lycopsamine-N-oxide (three diasteroisomers), 7-acetyllycopsamine-N-oxide, symphytine-N-oxide (two diasteroisomers) and 2'',3''-epoxyechiumine-N-oxide.

  17. Simultaneous high-performance liquid chromatographic determination of nitrate, nitrite, and organic pesticides in soil solution using a multidimensional column with ultraviolet detection

    International Nuclear Information System (INIS)

    Nkedi-Kizza, P.; Owusu-Yaw, J.

    1992-01-01

    In many fertilizer trials, the amount of nitrate-nitrogen in soil solution must be quantified frequently because nitrate is easily leached. Because pesticides are generally applied to cropland with fertilizers, quantitative information is needed on the concentration of these chemicals still available in the soil. Information on nitrite, nitrate and pesticide concentrations in food, water and environmental samples is essential because of their toxicity and potential for groundwater and surface water contamination. Most of the methods currently used for nitrate determination also account for nitrite, because nitrite and some organics act as interferences. Some of the existing analytical methods require sample reduction or derivatization, complex solvent mixtures or large sample volumes which make analysis times long. A High-Performance Liquid Chromatography (HPLC) method has been developed for the simultaneous determination of nitrate, nitrite and organic pesticides in soil solution samples and extracts using a multidimensional separator column with ultraviolet detection at 220 nm. The method is rapid and requires small sample volumes (20 μL). It is a sensitive method which is suitable for routine analyses of up to 100 samples per day. A comparison of this method with standard ion chromatography with conductivity detection showed very good agreement between the two methods for the analysis of NO3- and NO2-

  18. Electrochemically modulated liquid chromatography: Theoretical investigations and applications from the perspectives of chromatography and interfacial electrochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Keller, David W. [Iowa State Univ., Ames, IA (United States)

    2005-01-01

    Electrochemically modulated liquid chromatography (EMLC) employs a conductive material as both a stationary phase for chromatographic separations and as a working electrode for performing electrochemistry experiments. This dual functionality gives EMLC the capacity to manipulate chromatographic separations by changing the potential applied (Eapp) to the stationary phase with respect to an external reference. The ability to monitor retention as a function of Eapp provides a means to chromatographically monitor electrosorption processes at solid-liquid interfaces. In this dissertation, the retention mechanism for EMLC is examined from the perspective of electrical double layer theory and interfacial thermodynamics. From the chromatographic data, it is possible to determine the interfacial excess (Λ) of a solute and changes in interfacial tension (dγ) as a function of both Eapp and the supporting electrolyte concentration. Taken together, these two experimentally manipulated parameters can be examined within the context of the Gibbs adsorption equation to delineate the contribution of a variety of interfacial properties, including the charge of solute on the stationary phase and the potential of zero charge (PZC), to the mechanism behind EMLC-based retention. The chromatographic probing of interfacial phenomena is complemented by electroanalytical experiments that exploit the ability to monitor the electronic current flowing through an EMLC column. Cyclic voltammetry and chronoamperometry of an EMLC column are used to determine the electronic performance characteristics of an EMLC column. An electrochemical flow injection analysis of a column is provided in which the current required to maintain a constant Eapp is monitored and provides a way to examine the influence that acetonitrile and supporting electrolyte composition, flow rate, column backpressure, and ionic strength have on the structure of electrified interfaces.

  19. How to separate ionic liquids: Use of Hydrophilic Interaction Liquid Chromatography and mixed mode phases

    International Nuclear Information System (INIS)

    Lamouroux, C.

    2011-01-01

    This chromatographic study deals with the development of a convenient and versatile method to separate Room Temperature Ionic Liquids. Different modes of chromatography were studied. The study attempts to answer the following question: 'what were the most important interactions for the separation of ionic liquids?'. The results show that the essential interactions to assure a good retention of RTILs are the ionic ones and that hydrophobic interactions play a role in the selectivity of the separation. The separation of five imidazolium salt with a traditional dial columns in Hydrophilic Interaction Chromatography (HILIC) was demonstrated. It shows that neutral diol grafted column allows an important retention that we assume is due to the capability of diol to develop a thick layer of water. Furthermore, stationary phase based on mixed interaction associating ion exchange and hydrophobic properties were studied. Firstly, it will be argued that it is possible to separate RTILs with a convenient retention and resolution according to a reverse phase elution with the Primesep columns made of a brush type long alkyl chain with an embedded negatively charged functional group. Secondly, a successful separation of RTILs in HILIC mode with a mixed phase column containing a cationic exchanger and a hydrophobic octyl chain length will be demonstrated. (author)

  20. Surface-bonded ionic liquid stationary phases in high-performance liquid chromatography--a review.

    Science.gov (United States)

    Pino, Verónica; Afonso, Ana M

    2012-02-10

    Ionic liquids (ILs) are a class of ionic, nonmolecular solvents which remain in liquid state at temperatures below 100°C. ILs possess a variety of properties including low to negligible vapor pressure, high thermal stability, miscibility with water or a variety of organic solvents, and variable viscosity. IL-modified silica as novel high-performance liquid chromatography (HPLC) stationary phases have attracted considerable attention for their differential behavior and low free-silanol activity. Indeed, around 21 surface-confined ionic liquids (SCIL) stationary phases have been developed in the last six years. Their chromatographic behavior has been studied, and, despite the presence of a positive charge on the stationary phase, they showed considerable promise for the separation of neutral solutes (not only basic analytes), when operated in reversed phase mode. This aspect points to the potential for truly multimodal stationary phases. This review attempts to summarize the state-of-the-art about SCIL phases including their preparation, chromatographic behavior, and analytical performance. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Process of quantity determination of uranium by chromatography in liquid zone

    International Nuclear Information System (INIS)

    Muller, J.P.; Cojean, J.; Daubizit, M.

    1993-01-01

    The invention concerns a process of quantity determination of uranium by chromatography in liquid zone, usable to determine the quantity of uranium traces. Solutions to be treated can be aqueous or organic

  2. Qualitative and quantitative determination of ubiquinones by the method of high-efficiency liquid chromatography

    International Nuclear Information System (INIS)

    Yanotovskii, M.T.; Mogilevskaya, M.P.; Obol'nikova, E.A.; Kogan, L.M.; Samokhvalov, G.I.

    1986-01-01

    A method has been developed for the qualitative and quantitative determination of ubiquinones CoQ 6 -CoQ 10 , using high-efficiency reversed-phase liquid chromatography. Tocopherol acetate was used as the internal standard

  3. Determination of Aspartame, Caffeine, Saccharin, and Benzoic Acid in Beverages by High Performance Liquid Chromatography.

    Science.gov (United States)

    Delaney, Michael F.; And Others

    1985-01-01

    Describes a simple and reliable new quantitative analysis experiment using liquid chromatography for the determinaiton of caffeine, saccharin, and sodium benzoate in beverages. Background information, procedures used, and typical results obtained are provided. (JN)

  4. Experimental hydrophobicity parameters of perfluorinated alkylated substances from reversed-phase high performance liquid chromatography

    NARCIS (Netherlands)

    de Voogt, P.; Zurano, L.; Serné, P.; Haftka, J.J.H.

    2012-01-01

    Capacity factors of perfluorinated alkylated substances were obtained from isocratic reversed-phase high-performance liquid chromatography-mass spectrometry experiments at different organic modifier strengths of the mobile phase. The resulting capacity factor v. modifier strengths plots were

  5. Determination of maduramicin in feedingstuffs and premixtures by liquid chromatography : development, validation and interlaboratory study

    NARCIS (Netherlands)

    Jong, de J.; Stoisser, B.; Wagner, K.; Tomassen, M.J.H.; Driessen, J.J.M.; Hofman, P.; Putzka, H.A.

    2004-01-01

    A reversed-phase liquid chromatography method for determination of maduramicin in feedingstuffs and premixtures was developed, validated, and interlaboratory studied. The extraction solvent was methanol. Maduramicin was detected at 520 nm after postcolumn derivatization with vanillin. Recovery was

  6. Assay for dihydroorotase using high-performance liquid chromatography with radioactivity detection

    International Nuclear Information System (INIS)

    Mehdi, S.; Wiseman, J.S.

    1989-01-01

    An assay for measuring dihydroorotase activity was devised. Radiolabeled substrate and product were separated by high-performance liquid chromatography using a reverse-phase column with ion-pairing, and the radioactivity was quantitated by flow detection

  7. An efficient hydrophilic interaction liquid chromatography separation of 7 phospholipid classes based on a diol column

    NARCIS (Netherlands)

    Zhu, C.; Dane, A.; Spijksma, G.; Wang, M.; Greef, J. van der; Luo, G.; Hankemeier, T.; Vreeken, R.J.

    2012-01-01

    A hydrophilic interaction liquid chromatography (HILIC) - ion trap mass spectrometry method was developed for separation of a wide range of phospholipids. A diol column which is often used with normal phase chromatography was adapted to separate different phospholipid classes in HILIC mode using a

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

    Science.gov (United States)

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

    2017-07-01

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

  9. Determination of methylphenidate in Calliphorid larvae by liquid-liquid extraction and liquid chromatography mass spectrometry - Forensic entomotoxicology using an in vivo rat brain model

    DEFF Research Database (Denmark)

    Bushby, Sarah K.; Thomas, Nicky; Priemel, Petra A.

    2012-01-01

    and Calliphorid larvae) by liquid-liquid extraction with recovery of >80%, and quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The LC-MS/MS assay was validated for entomotoxicological use and initially applied to male Sprague-Dawley rats (n=6) that were dosed with MPH (20mg/kg) ante...

  10. Chromatography.

    Science.gov (United States)

    Brantley, L. Reed, Sr.; Demanche, Edna L.; Klemm, E. Barbara; Kyselka, Will; Phillips, Edwin A.; Pottenger, Francis M.; Yamamoto, Karen N.; Young, Donald B.

    This booklet presents some activities on chromatography. Directions for preparing leaf pigment extracts using alcohol are given, and paper chromatography and thin-layer chromatography are described as modifications of the basic principles of chromatography. (KHR)

  11. Arsenic speciation by liquid chromatography coupled with ionspray tandem mass spectrometry

    DEFF Research Database (Denmark)

    Corr, J. J.; Larsen, Erik Huusfeldt

    1996-01-01

    Ionspray mass spectrometry, a well established organic analysis technique, has been coupled to high-performance liquid chromatography for speciation of organic arsenic compounds, The ionspray source and differentially pumped interface of the mass spectrometer were operated in dual modes...... fragmentation patterns showing molecular dissociation through an expected common product ion were obtained for the four arsenosugars, Molecular mode detection was utilized for qualitative verification of speciation analysis by high-performance liquid chromatography coupled to inductively coupled plasma mass...

  12. Liquid chromatography-mass spectrometry coupling by the intermediary of a liquid micro chromatography-electro spray interface; Couplage chromatographie liquide-spectrometrie de masse par l`intermediaire d`une interface electrospray-microchromatographie liquide

    Energy Technology Data Exchange (ETDEWEB)

    Gillard Factor, C

    1996-12-06

    The objective of this work is to realize a liquid chromatography- mass spectrometry coupling by the intermediary of an electro spray interface and the evaluation of performances of tis analytical tool to study pollutants in water, and more particularly pesticides whom maximum admissible concentration in a table water is 0.1{mu}g/l. This study has allowed to bring to the fore the interest of the ionization mode by electro spray in a LC/MS coupling to identify and quantify pesticides in the state of traces without treating the sample. Then, it was demonstrated the usefulness of this analytical tool to detect high molecular masses molecules. (N.C.)

  13. Tryptophan and kynurenine determination in human hair by liquid chromatography.

    Science.gov (United States)

    Dario, Michelli F; Freire, Thamires Batello; Pinto, Claudinéia Aparecida Sales de Oliveira; Prado, María Segunda Aurora; Baby, André R; Velasco, Maria Valéria R

    2017-10-15

    Tryptophan, an amino acid found in hair proteinaceous structure is used as a marker of hair photodegradation. Also, protein loss caused by several chemical/physical treatments can be inferred by tryptophan quantification. Kynurenine is a photo-oxidation product of tryptophan, expected to be detected when hair is exposed mainly to UVB (290-320nm) radiation range. Tryptophan from hair is usually quantified directly as a solid or after alkaline hydrolysis, spectrofluorimetrically. However, these types of measure are not sufficiently specific and present several interfering substances. Thus, this work aimed to propose a quantification method for both tryptophan and kynurenine in hair samples, after alkali hydrolysis process, by using high-performance liquid chromatography (HPLC) with fluorimetric and UV detection. The tryptophan and kynurenine quantification method was developed and validated. Black, white, bleached and dyed (blond and auburn) hair tresses were used in this study. Tryptophan and kynurenine were separated within ∼9min by HPLC. Both black and white virgin hair samples presented similar concentrations of tryptophan, while bleaching caused a reduction in the tryptophan content as well as dyeing process. Unexpectedly, UV/vis radiation did not promote significantly the conversion of tryptophan into its photo-oxidation product and consequently, kynurenine was not detected. Thus, this works presented an acceptable method for quantification of tryptophan and its photooxidation metabolite kynurenine in hair samples. Also, the results indicated that bleaching and dyeing processes promoted protein/amino acids loss but tryptophan is not extensively degraded in human hair by solar radiation. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Liquid chromatography method to determine polyamines in thermosetting polymers

    Energy Technology Data Exchange (ETDEWEB)

    Dopico-Garcia, M.S. [Laboratorio de Quimica - Centro de Investigacions Tecnoloxicas, Universidade da Coruna, Campus de Esteiro s/n, 15403 Ferrol (Spain); Centro Galego do Plastico, A Cabana s/n, 15590 Ferrol (Spain); Lopez-Vilarino, J.M. [Laboratorio de Quimica - Centro de Investigacions Tecnoloxicas, Universidade da Coruna, Campus de Esteiro s/n, 15403 Ferrol (Spain); Fernandez-Martinez, G. [Unidad de Tecnicas Cromatograficas, Servizos de Apoio a Investigacion, Edificio Servizos Centrais de Investigacion, Universidade da Coruna, Campus de Elvina s/n, 15071 A Coruna (Spain); Gonzalez-Rodriguez, M.V., E-mail: victoria@udc.es [Dpto. de Quimica Analitica - E.U. Politecnica, Universidade da Coruna, Avda. 19 de Febrero s/n, 15405 Ferrol (Spain)

    2010-05-14

    A simple, robust and sensitive analytical method to determine three polyamines commonly used as hardeners in epoxy resin systems and in the manufacture of polyurethane is reported. The studied polyamines are: one tetramine, TETA (triethylenetetramine), and two diamines, IPDA (Isophorone diamine) and TCD-diamine (4,7-methano-1H-indene-5,?-dimethanamine, octahydro-). The latter has an incompletely defined structure, and, as far as we know, has not been previously determined by other methods. All three polyamines contain primary amines; TETA also contains secondary amines. The analytical method involves derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate, used for the first time for these compounds, followed by high performance liquid chromatography (HPLC) analysis with a fluorescence (FL) detector ({lambda} excitation 248 nm, {lambda} emision 395 nm). The HPLC-DAD-LTQ Orbitrap MS was used in order to provide structural information about the obtained derivatized compounds. The hybrid linear ion trap LTQ Orbitrap mass spectrometer has been introduced in recent years and provides a high mass accuracy. The structures of the derivatized analytes were identified from the protonated molecular ions [M+H]{sup +} and corresponded to the fully labelled analytes. The following analytical parameters were determined for the method using the HPLC-FL: linearity, precision (2.5-10%), instrumental precision intraday (0.8-1.5%) and interday (2.9-6.3%), and detection limits (0.02-0.14 mg L{sup -1}). The stability of stock solutions and derivatized compounds was also investigated. The method was applied to determine the amine free content in epoxy resin dust collected in workplaces.

  15. Liquid chromatography method to determine polyamines in thermosetting polymers.

    Science.gov (United States)

    Dopico-García, M S; López-Vilariño, J M; Fernández-Martínez, G; González-Rodríguez, M V

    2010-05-14

    A simple, robust and sensitive analytical method to determine three polyamines commonly used as hardeners in epoxy resin systems and in the manufacture of polyurethane is reported. The studied polyamines are: one tetramine, TETA (triethylenetetramine), and two diamines, IPDA (Isophorone diamine) and TCD-diamine (4,7-methano-1H-indene-5,?-dimethanamine, octahydro-). The latter has an incompletely defined structure, and, as far as we know, has not been previously determined by other methods. All three polyamines contain primary amines; TETA also contains secondary amines. The analytical method involves derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate, used for the first time for these compounds, followed by high performance liquid chromatography (HPLC) analysis with a fluorescence (FL) detector (lambda excitation 248nm, lambda emision 395nm). The HPLC-DAD-LTQ Orbitrap MS was used in order to provide structural information about the obtained derivatized compounds. The hybrid linear ion trap LTQ Orbitrap mass spectrometer has been introduced in recent years and provides a high mass accuracy. The structures of the derivatized analytes were identified from the protonated molecular ions [M+H](+) and corresponded to the fully labelled analytes. The following analytical parameters were determined for the method using the HPLC-FL: linearity, precision (2.5-10%), instrumental precision intraday (0.8-1.5%) and interday (2.9-6.3%), and detection limits (0.02-0.14mgL(-1)). The stability of stock solutions and derivatized compounds was also investigated. The method was applied to determine the amine free content in epoxy resin dust collected in workplaces. Copyright 2010 Elsevier B.V. All rights reserved.

  16. Liquid chromatography method to determine polyamines in thermosetting polymers

    International Nuclear Information System (INIS)

    Dopico-Garcia, M.S.; Lopez-Vilarino, J.M.; Fernandez-Martinez, G.; Gonzalez-Rodriguez, M.V.

    2010-01-01

    A simple, robust and sensitive analytical method to determine three polyamines commonly used as hardeners in epoxy resin systems and in the manufacture of polyurethane is reported. The studied polyamines are: one tetramine, TETA (triethylenetetramine), and two diamines, IPDA (Isophorone diamine) and TCD-diamine (4,7-methano-1H-indene-5,?-dimethanamine, octahydro-). The latter has an incompletely defined structure, and, as far as we know, has not been previously determined by other methods. All three polyamines contain primary amines; TETA also contains secondary amines. The analytical method involves derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate, used for the first time for these compounds, followed by high performance liquid chromatography (HPLC) analysis with a fluorescence (FL) detector (λ excitation 248 nm, λ emision 395 nm). The HPLC-DAD-LTQ Orbitrap MS was used in order to provide structural information about the obtained derivatized compounds. The hybrid linear ion trap LTQ Orbitrap mass spectrometer has been introduced in recent years and provides a high mass accuracy. The structures of the derivatized analytes were identified from the protonated molecular ions [M+H] + and corresponded to the fully labelled analytes. The following analytical parameters were determined for the method using the HPLC-FL: linearity, precision (2.5-10%), instrumental precision intraday (0.8-1.5%) and interday (2.9-6.3%), and detection limits (0.02-0.14 mg L -1 ). The stability of stock solutions and derivatized compounds was also investigated. The method was applied to determine the amine free content in epoxy resin dust collected in workplaces.

  17. Separation of anionic oligosaccharides by high-performance liquid chromatography

    International Nuclear Information System (INIS)

    Green, E.D.; Baenziger, J.U.

    1986-01-01

    The authors have developed methods for rapid fractionation of anionic oligosaccharides containing sulfate and/or sialic acid moieties by high-performance liquid chromatography (HPLC). Ion-exchange HPLC on amine-bearing columns (Micropak AX-10 and AX-5) at pH 4.0 is utilized to separate anionic oligosaccharides bearing zero, one, two, three, or four charges, independent of the identity of the anionic moieties (sulfate and/or sialic acid). Ion-exchange HPLC at pH 1.7 allows separation of neutral, mono-, di-, and tetrasialylated, monosulfated, and disulfated oligosaccharides. Oligosaccharides containing three sialic acid residues and those bearing one each of sulfate and sialic acid, however, coelute at pH 1.7. Since the latter two oligosaccharide species separate at pH 4.0, analysis at pH 4.0 followed by analysis at pH 1.7 can be utilized to completely fractionate complex mixtures of sulfated and sialylated oligosaccharides. Ion-suppression amine adsorption HPLC has previously been shown to separate anionic oligosaccharides on the basis of net carbohydrate content (size). In this study they demonstrate the utility of ion-suppression amine adsorption HPLC for resolving sialylated oligosaccharide isomers which differ only in the linkages of sialic acid residues (α2,3 vs α2,6) and/or location of α2,3- and α2,6-linked sialic acid moieties on the peripheral branches of oligosaccharides. These two methods can be used in tandem to separate oligosaccharides, both analytically and preparatively, based on their number, types, and linkages of anionic moieties

  18. Study of high performance liquid chromatography fingerprint for traditional chinese medicine yigongningxue oral liquid

    International Nuclear Information System (INIS)

    Feng, C.; Ruan, J.L.

    2010-01-01

    A simple, reliable and accurate fingerprinting method has been developed for quality control of YiGongNingXue oral liquid. The separation was done by reverse phase chromatography using Zorbax eclipse XDB C/sub 18/ column (250mmx4.6mmi. d. with 5.0 micro m particle size) and detection at 246nm. Methanol (5-95 % in 70 min)-buffer solution (water-phosphorica cid, pH 3.0, 95-0 percent in 70 min) as mobile phase for linear gradient elution. The flow rate was 1.0 mLmin/sup 1/ and the column temperature was at 25 deg. C. The similarity of 20 batches of YGNX oral liquid was more than 90 %. Also 15 common peaks of chromatogram have been detected, ten of them were identified by comparing fingerprint chromatogram with reference substances The HPLC fingerprint can be used to control the quality of YiGongNingXue oral liquid. (author)

  19. Development of an on-line mixed-mode gel liquid chromatography×reversed phase liquid chromatography method for separation of water extract from Flos Carthami.

    Science.gov (United States)

    Wang, Yu-Qing; Tang, Xu; Li, Jia-Fu; Wu, Yun-Long; Sun, Yu-Ying; Fang, Mei-Juan; Wu, Zhen; Wang, Xiu-Min; Qiu, Ying-Kun

    2017-10-13

    A novel on-line comprehensive two-dimensional liquid chromatography (2D-LC) method by coupling mixed-mode gel liquid chromatography (MMG-LC) with reversed phase liquid chromatography (RPLC) was developed. A mixture of 17 reference compounds was used to study the separation mechanism. A crude water extract of Flos Carthami was applied to evaluate the performance of the novel 2D-LC system. In the first dimension, the extract was eluted with a gradient of water/methanol over a cross-linked dextran gel Sephadex LH-20 column. Meanwhile, the advantages of size exclusion, reversed phase partition and adsorption separation mechanism were exploited before further on-line reversed phase purification on the second dimension. This novel on-line mixed-mode Sephadex LH-20×RPLC method provided higher peak resolution, sample processing ability (2.5mg) and better orthogonality (72.9%) versus RPLC×RPLC and hydrophilic interaction liquid chromatography (HILIC)×RPLC. To the best of our knowledge, this is the first report of a mixed-mode Sephadex LH-20×RPLC separation method with successful applications in on-line mode, which might be beneficial for harvesting targets from complicated medicinal plants. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Purification Efficacy of Synthetic Cannabinoid Conjugates Using High-Pressure Liquid Chromatography

    Science.gov (United States)

    conducted using high-pressure liquid chromatography and gradient screens to determine the most effective means of purifying the SC:dark quencher conjugates...to obtain the highest yields and purity. The purity was verified using liquid chromatographycoupled mass spectroscopy and nuclear magnetic resonance.

  1. Prostate cell membrane chromatography-liquid chromatography-mass spectrometry for screening of active constituents from Uncaria rhynchophylla.

    Science.gov (United States)

    He, Jianyu; Han, Shengli; Yang, Fangfang; Zhou, Nan; Wang, Sicen

    2013-01-01

    Uncaria rhynchophylla is a traditional Chinese medicinal herb used to treat hypertension and convulsive disorders such as epilepsy. Rat prostate cell membrane chromatography combined with liquid chromatography-mass spectrometry (LC-MS) was used to identify active constituents from U. rhynchophylla extracts. Four compounds (corynoxeine, isorhynchophylline, isocorynoxeine and rhynchophylline) were discovered. Competitive binding assay results indicated that the four compounds were in direct competition at a single common binding site and interacted with α1A adrenergic receptors (α1A-AR) in a manner similar to tamsulosin. Affinity constant values of the four compounds binding with α1A-AR were also measured using rat prostate cell membrane chromatography (CMC). Finally, their pharmacodynamic effects were tested on rat caudal arteries. This CMC combined LC-MS system offers a means of drug discovery by screening natural medicinal herbs for new pharmacologically active molecules targeting specific receptors.

  2. [Analysis of microalbuminuria with immunonephelometry and high performance liquid chromatography. Evaluation of new criteria].

    Science.gov (United States)

    Markó, Lajos; Molnár, Gergo Attila; Wagner, Zoltán; Koszegi, Tamás; Matus, Zoltán; Mohás, Márton; Kuzma, Mónika; Szijártó, István András; Wittmann, István

    2008-01-13

    Hypertension as well as type 2 diabetes mellitus is a major factor in population mortality. Both diseases damage the endothelium, the early sign of which is microalbuminuria, which can be screened by dipstick and can be diagnosed by using immuno-based and high performance liquid chromatography methods. Using high performance liquid chromatography, the non-immunoreactive albumin can be detected as well. The authors aimed at the examination of albuminuria in the case of immunonephelometrically negative patients with high performance liquid chromatography, in diabetic and hypertensive and non-diabetic hypertensive populations. The authors also wanted to compare the present (albumin-creatinine ratio: male: > or =2.5 mg/mmol, female: > or =3.5 mg/mmol) and a new criteria of the Heart Outcomes Prevention Evaluation study (patients without diabetes: immunological method, > or =0.7 mg/mmol; high performance liquid chromatography, > or =3.1 mg/mmol; individuals with diabetes: immunological method, > or =1.4 mg/mmol; high performance liquid chromatography, > or =5.2 mg/mmol) of microalbuminuria. Examination of fresh urines of 469 microalbuminuria negative patients by dipstick were performed by immunonephelometry. Patients, who were microalbuminuria negative by immunonephelometry as well, were further analyzed by high performance liquid chromatography using the Accumintrade mark Kit, based on size-exclusion chromatography. Three times higher albuminuria were found with high performance liquid chromatography than with immunonephelometry. The intraindividual coefficient of variation did not differ in the two methods (37 +/- 31% vs. 40 +/- 31%, p = 0.869; immunonephelometry vs. high performance liquid chromatography; mean +/- standard deviation). Using the present criteria for microalbuminuria, 43% of immunonephelometrically negative patients proved to be microalbuminuric by high performance liquid chromatography. Using the new criteria of the Heart Outcomes Prevention

  3. Preparation and evaluation of surface-bonded tricationic ionic liquid silica as stationary phases for high-performance liquid chromatography.

    Science.gov (United States)

    Qiao, Lizhen; Shi, Xianzhe; Lu, Xin; Xu, Guowang

    2015-05-29

    Two tricationic ionic liquids were prepared and then bonded onto the surface of supporting silica materials through "thiol-ene" click chemistry as new stationary phases for high-performance liquid chromatography. The obtained columns of tricationic ionic liquids were evaluated respectively in the reversed-phase liquid chromatography (RPLC) mode and hydrophilic interaction liquid chromatography (HILIC) mode, and possess ideal column efficiency of 80,000 plates/m in the RPLC mode with naphthalene as the test solute. The tricationic ionic liquid stationary phases exhibit good hydrophobic and shape selectivity to hydrophobic compounds, and RPLC retention behavior with multiple interactions. In the HILIC mode, the retention and selectivity were evaluated through the efficient separation of nucleosides and bases as well as flavonoids, and the typical HILIC retention behavior was demonstrated by investigating retention changes of hydrophilic solutes with water volume fraction in mobile phase. The results show that the tricationic ionic liquid columns possess great prospect for applications in analysis of hydrophobic and hydrophilic samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Application of Ionic Liquids in High Performance Reversed-Phase Chromatography

    Directory of Open Access Journals (Sweden)

    Wentao Bi

    2009-06-01

    Full Text Available Ionic liquids, considered “green” chemicals, are widely used in many areas of analytical chemistry due to their unique properties. Recently, ionic liquids have been used as a kind of novel additive in separation and combined with silica to synthesize new stationary phase as separation media. This review will focus on the properties and mechanisms of ionic liquids and their potential applications as mobile phase modifier and surface-bonded stationary phase in reversed-phase high performance liquid chromatography (RP-HPLC. Ionic liquids demonstrate advantages and potential in chromatographic field.

  5. Quality evaluation of moluodan concentrated pill using high-performance liquid chromatography fingerprinting coupled with chemometrics.

    Science.gov (United States)

    Tao, Lingyan; Zhang, Qing; Wu, Yongjiang; Liu, Xuesong

    2016-12-01

    In this study, a fast and effective high-performance liquid chromatography method was developed to obtain a fingerprint chromatogram and quantitative analysis simultaneously of four indexes including gallic acid, chlorogenic acid, albiflorin and paeoniflorin of the traditional Chinese medicine Moluodan Concentrated Pill. The method was performed by using a Waters X-bridge C 18 reversed phase column on an Agilent 1200S high-performance liquid chromatography system coupled with diode array detection. The mobile phase of the high-performance liquid chromatography method was composed of 20 mmol/L phosphate solution and acetonitrile with a 1 mL/min eluent velocity, under a detection temperature of 30°C and a UV detection wavelength of 254 nm. After the methodology validation, 16 batches of Moluodan Concentrated Pill were analyzed by this high-performance liquid chromatography method and both qualitative and quantitative evaluation results were achieved by similarity analysis, principal component analysis and hierarchical cluster analysis. The results of these three chemometrics were in good agreement and all indicated that batch 10 and batch 16 showed significant differences with the other 14 batches. This suggested that the developed high-performance liquid chromatography method could be applied in the quality evaluation of Moluodan Concentrated Pill. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Isolation and purification of six iridoid glycosides from gardenia jasminoides fruit by medium-pressure liquid chromatography combined with macroporous resin chromatography.

    Science.gov (United States)

    Wang, Yun; Liu, Hui; Shen, Lifeng; Yao, Lan; Ma, Yinlian; Yu, Dingrong; Chen, Jianhong; Li, Puling; Chen, Ying; Zhang, Cun

    2015-12-01

    Gardeniae fructus is one of the most frequently used herbs in traditional Chinese medicine. In the present study, a process for the enrichment of six iridoid glycosides from Gardeniae fructus was developed using medium-pressure liquid chromatography combined with macroporous resin and reversed-phase chromatography. The purities of different fractions from Gardeniae fructus were assessed using quantitative high-performance liquid chromatography. After fractionation using HPD-100 column chromatography, a 30% ethanol fraction was selected based on high-performance liquid chromatography and liquid chromatography with mass spectrometry qualitative analysis to separate and purify. Based on the orientation analysis results, six compounds-deacetyl asperulosidic acid methyl ester, gardenoside, ixoroside, scandoside methyl ester, genipin-1-O-β-d-gentiobioside, and geniposide-were successfully isolated and purified in three to four combined steps from Gardeniae fructus. The purities of these compounds were found by high-performance liquid chromatography analysis to be 97.9, 98.1, 95.5, 96.3, 97.1, and 98.7%, respectively. Moreover, their structures were elucidated by NMR spectroscopy and liquid chromatography with tandem mass spectrometry. The separation process was highly efficient, rapid, and accurate, making it a potential approach for the large-scale production of iridoids in the laboratory and providing several marker compounds for quality control. This procedure may be meaningful for the purification of other natural products used in traditional Chinese medicine. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Analysis of chlorpheniramine in human urine samples using dispersive liquid-liquid microextraction combined with high-performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Mehdi Maham

    2014-09-01

    Full Text Available A simple and environmentally friendly microextraction technique was used for determination of chlorpheniramine (CPM, an antihistamine drug, in human urine samples using dispersive liquid-liquid microextraction (DLLME followed by high performance liquid chromatography with diode array detection (HPLC-DAD. In this extraction technique, an appropriate mixture of acetonitrile (disperser solvent and carbon tetrachloride (extraction solvent was rapidly injected into the urine sample containing the target analyte. Tiny droplets of extractant were formed and dispersed into the sample solution and then sedimented at the bottom of the conical test tube by centrifugation. Under optimal conditions, the calibration curve was linear in the range of 0.055-5.5 µg mL-1, with a detection limit of 16.5 ng mL-1. This proposed method was successfully applied to the analysis of real urine samples. Low consumption of toxic organic solvents, simplicity of operation, low cost and acceptable figures of merit are the main advantages of the proposed technique.

  8. Optimization of an online heart-cutting multidimensional gas chromatography clean-up step for isotopic ratio mass spectrometry and simultaneous quadrupole mass spectrometry measurements of endogenous anabolic steroid in urine.

    Science.gov (United States)

    Casilli, Alessandro; Piper, Thomas; de Oliveira, Fábio Azamor; Padilha, Monica Costa; Pereira, Henrique Marcelo; Thevis, Mario; de Aquino Neto, Francisco Radler

    2016-11-01

    Measuring carbon isotope ratios (CIRs) of urinary analytes represents a cornerstone of doping control analysis and has been particularly optimized for the detection of the misuse of endogenous steroids. Isotope ratio mass spectrometry (IRMS) of appropriate quality, however, necessitates adequate purities of the investigated steroids, which requires extensive pre-analytical sample clean-up steps due to both the natural presence of the target analytes and the high complexity of the matrix. In order to accelerate the sample preparation and increase the automation of the process, the use of multidimensional gas chromatography (MDGC) prior to IRMS experiments, was investigated. A well-established instrumental configuration based on two independent GC ovens and one heart-cutting device was optimized. The first dimension (1D) separation was obtained by a non-polar column which assured high efficiency and good loading capacity, while the second dimension (2D), based on a mid-polar stationary phase, provided good selectivity. A flame ionization detector monitored the 1D, and the 2D was simultaneously recorded by isotope ratio and quadrupole mass spectrometry. The assembled MDGC set-up was applied for measuring testosterone, 5α- and 5β-androstanediol, androsterone, and etiocholanolone as target compounds and pregnanediol as endogenous reference compound. The urine sample were pretreated by conventional sample preparation steps comprising solid-phase extraction, hydrolysis, and liquid-liquid extraction. The extract obtained was acetylated and different aliquots were injected into the MDGC system. Two high performance liquid chromatography steps, conventionally adopted prior to CIR measurements, were replaced by the MDGC approach. The obtained values were consistent with the conventional ones. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  9. Design of a compressed air modulator to be used in comprehensive multidimensional gas chromatography and its application in the determination of pesticide residues in grapes.

    Science.gov (United States)

    Pizzutti, Ionara R; Vreuls, René J J; de Kok, André; Roehrs, Rafael; Martel, Samile; Friggi, Caroline A; Zanella, Renato

    2009-04-10

    In this study, a new modulator that is simple, robust and presents low operation costs, was developed. This modulator uses compressed air to cool two small portions in the first centimeters of the second chromatographic column of a comprehensive multidimensional gas chromatography (GCxGC) system. The results show a variation in the peak area less than 3 and 5% to alkanes and pesticides, respectively. The standard deviations for the retention times in the first and second dimension are around 0.05 min and 0.05s for all the compounds. The system was optimized with n-alkanes. The GCxGC system proposed was applied in the determination of pyrethroid pesticides (bifenthrin, cypermethrin, deltamethrin, fenvalerate, esfenvalerate, cis- and trans-permethrin) in grape samples. Samples were extracted by the mini-Luke modified method and pesticides were quantified by comprehensive multidimensional gas chromatography with micro electron-capture detection (microECD). The values of method limit of quantification (LOQ) were 0.01-0.02 mg kg(-1) for all studied pyrethroid and the values of recovery were between 94.3 and 115.2%, with good precision (RSDcompressed air has the potential for application in the analysis of a wider range of pesticide residues in other commodities since it provides low values of LOQ with acceptable accuracy and precision.

  10. Recent advances in liquid and gas chromatography methodology for extending coverage of the metabolome.

    Science.gov (United States)

    Haggarty, Jennifer; Burgess, Karl Ev

    2017-02-01

    The metabolome is the complete complement of metabolites (small organic biomolecules). In order to comprehensively understand the effect of stimuli on a biological system, it is important to detect as many of the metabolites within that system as possible. This review briefly describes some new advances in liquid and gas chromatography to improve coverage of the metabolome, including the serial combination of two columns in tandem, column switching and different variations of two-dimensional chromatography. Supercritical fluid chromatography could provide complimentary data to liquid and gas chromatography. Although there have been many recent advancements in the field of metabolomics, it is evident that a combination, rather than a single method, is required to approach full coverage of the metabolome. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  11. Automated multi-dimensional liquid chromatography : sample preparation and identification of peptides from human blood filtrate

    NARCIS (Netherlands)

    Machtejevas, Egidijus; John, Harald; Wagner, Knut; Standker, Ludger; Marko-Varga, Gyorgy; Georg Forssmann, Wolf; Bischoff, Rainer; K. Unger, Klaus

    2004-01-01

    A comprehensive on-line sample clean-up with an integrated two-dimensional HPLC system was developed for the analysis of natural peptides. Samples comprised of endogenous peptides with molecular weights up to 20 kDa were generated from human hemofiltrate (HF) obtained from patients with chronic

  12. Application of liquid column chromatography to preconcentration, separation and determination of platinum metals

    International Nuclear Information System (INIS)

    Alimarin, I.P.; Basova, E.M.; Bol'shova, T.A.; Ivanov, V.M.

    1986-01-01

    Separation and determination of platimum metals using the methods of adsorption, ion-pair, ion-exchange, distributing and sieve chromatography are discussed in the review of literature in 1971-1984. Separation and determination of metals as chelates using the method of adsorption and ion-pair chromatograpy are noted to be most perspective directions of developing highly effective liquid chromatography of inorganic systems

  13. Immunoaffinity chromatography of abscisic acid combined with electrospray liquid chromatography–mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Hradecká, Veronika; Novák, Ondřej; Havlíček, Libor; Strnad, Miroslav

    2007-01-01

    Roč. 847, č. 2 (2007), s. 162-173 ISSN 1570-0232 R&D Projects: GA MŠk(CZ) LC06034; GA AV ČR IBS5038351 Institutional research plan: CEZ:AV0Z50380511 Source of funding: V - iné verejné zdroje ; V - iné verejné zdroje Keywords : abscisic acid * immunoaffinity chromatography * liquid chromatography-mass spectrometry Subject RIV: ED - Physiology Impact factor: 2.935, year: 2007

  14. Monodisperse microbeads of hypercrosslinked polystyrene for liquid and supercritical fluid chromatography

    Science.gov (United States)

    Tsyurupa, M. P.; Blinnikova, Z. K.; Il'in, M. M.; Davankov, V. A.; Parenago, O. O.; Pokrovskii, O. I.; Usovich, O. I.

    2015-11-01

    Monodisperse styrene-divinylbenzene (1 wt %) copolymer microbeads are obtained via the elaborate method of high-productivity precipitation polymerization. The crosslinking of this copolymer with chloromethyl methyl ether in the presence of Friedel-Crafts catalyst yields porous hypercrosslinked polymers with degrees of crosslinking that range from 200 to 500%. Microbead sorbents are shown to be suited for selective stationary phases for high-performance liquid chromatography and supercritical fluid chromatography.

  15. Improved method for the determination of the cortisol production rate using high-performance liquid chromatography and liquid scintillation counting

    NARCIS (Netherlands)

    van Ingen, H. E.; Endert, E.

    1988-01-01

    Two new methods for the determination of the cortisol production rate using reversed-phase high-performance liquid chromatography are described. One uses ultraviolet detection at 205 nm, the other on-line post-column derivatization with benzamidine, followed by fluorimetric detection. The specific

  16. Characterization of natural organic colorants in historical and art objects by high-performance liquid chromatography.

    Science.gov (United States)

    Pauk, Volodymyr; Barták, Petr; Lemr, Karel

    2014-12-01

    High-performance liquid chromatography plays an important role in analysis of historical organic colorants. A number of papers have been published in this field over the last 30 years. Classification of the most commonly used natural dyes and an overview of high-performance liquid chromatography methods with main focus on recent works (2008 to the beginning of 2014) are provided. The review deals with an entire analytical protocol covering sample preparation, chromatographic separation, and suitable detection (UV/visible and fluorescent spectroscopy and mass spectrometric techniques). High-performance liquid chromatography has been successfully used in the complete characterization of some organic dyestuffs present in historical and art objects. The possibilities and difficulties for identification of natural sources of historical colorants are also discussed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Screening and quantitative determination of twelve acidic and neutral pharmaceuticals in whole blood by liquid-liquid extraction and liquid chromatography-tandem mass spectrometry

    DEFF Research Database (Denmark)

    Simonsen, Kirsten Wiese; Steentoft, Anni; Buck, Maike

    2010-01-01

    . The method was fully validated for salicylic acid, paracetamol, phenobarbital, carisoprodol, meprobamate, topiramate, etodolac, chlorzoxazone, furosemide, ibuprofen, warfarin, and salicylamide. The method also tentatively includes thiopental, theophylline, piroxicam, naproxen, diclophenac, and modafinil......We describe a multi-method for simultaneous identification and quantification of 12 acidic and neutral compounds in whole blood. The method involves a simple liquid-liquid extraction, and the identification and quantification are performed using liquid chromatography-tandem mass spectrometry...

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

    Science.gov (United States)

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

    2016-03-18

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

  19. High-performance liquid chromatography of oligoguanylates at high pH

    Science.gov (United States)

    Stribling, R.; Deamer, D. (Principal Investigator)

    1991-01-01

    Because of the stable self-structures formed by oligomers of guanosine, standard high-performance liquid chromatography techniques for oligonucleotide fractionation are not applicable. Previously, oligoguanylate separations have been carried out at pH 12 using RPC-5 as the packing material. While RPC-5 provides excellent separations, there are several limitations, including the lack of a commercially available source. This report describes a new anion-exchange high-performance liquid chromatography method using HEMA-IEC BIO Q, which successfully separates different forms of the guanosine monomer as well as longer oligoguanylates. The reproducibility and stability at high pH suggests a versatile role for this material.

  20. Glucose and glycerol concentrations and their tracer enrichment measurements using liquid chromatography tandem mass spectrometry

    DEFF Research Database (Denmark)

    Bornø, Andreas; Foged, Lene; van Hall, Gerrit

    2014-01-01

    The present study describes a new liquid chromatography tandem mass spectrometry method for high-throughput quantification of glucose and glycerol in human plasma using stable isotopically labeled internal standards and is suitable for simultaneous measurements of glucose and glycerol enrichments...... of variation were 2.0% and 9.7%, respectively. After derivatization, plasma samples were stable for at least 14 days. In conclusion, we have developed and validated a novel, accurate, and sensitive high-throughput liquid chromatography tandem mass spectrometry method for simultaneous determination of glucose...

  1. A simple liquid extraction protocol for overcoming the ion suppression of triacylglycerols by phospholipids in liquid chromatography mass spectrometry studies.

    Science.gov (United States)

    Araujo, Pedro; Tilahun, Ephrem; Breivik, Joar Fjørtoft; Abdulkader, Bashir M; Frøyland, Livar; Zeng, Yingxu

    2016-02-01

    It is well-known that triacylglycerol (TAG) ions are suppressed by phospholipid (PL) ions in regiospecific analysis of TAG by mass spectrometry (MS). Hence, it is essential to remove the PL during sample preparation prior to MS analysis. The present article proposes a cost-effective liquid-liquid extraction (LLE) method to remove PL from TAG in different kinds of biological samples by using methanol, hexane and water. High performance thin layer chromatography confirmed the lack of PL in krill oil and salmon liver samples, submitted to the proposed LLE protocol, and liquid chromatography tandem MS confirmed that the identified TAG ions were highly enhanced after implementing the LLE procedure. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Bacterial Cell Wall Precursor Phosphatase Assays Using Thin-layer Chromatography (TLC) and High Pressure Liquid Chromatography (HPLC).

    Science.gov (United States)

    Pazos, Manuel; Otten, Christian; Vollmer, Waldemar

    2018-03-20

    Peptidoglycan encases the bacterial cytoplasmic membrane to protect the cell from lysis due to the turgor. The final steps of peptidoglycan synthesis require a membrane-anchored substrate called lipid II, in which the peptidoglycan subunit is linked to the carrier lipid undecaprenol via a pyrophosphate moiety. Lipid II is the target of glycopeptide antibiotics and several antimicrobial peptides, and is degraded by 'attacking' enzymes involved in bacterial competition to induce lysis. Here we describe two protocols using thin-layer chromatography (TLC) and high pressure liquid chromatography (HPLC), respectively, to assay the digestion of lipid II by phosphatases such as Colicin M or the LXG toxin protein TelC from Streptococcus intermedius . The TLC method can also monitor the digestion of undecaprenyl (pyro)phosphate, whereas the HPLC method allows to separate the di-, mono- or unphosphorylated disaccharide pentapeptide products of lipid II.

  3. Lipidomic analysis of biological samples: Comparison of liquid chromatography, supercritical fluid chromatography and direct infusion mass spectrometry methods.

    Science.gov (United States)

    Lísa, Miroslav; Cífková, Eva; Khalikova, Maria; Ovčačíková, Magdaléna; Holčapek, Michal

    2017-11-24

    Lipidomic analysis of biological samples in a clinical research represents challenging task for analytical methods given by the large number of samples and their extreme complexity. In this work, we compare direct infusion (DI) and chromatography - mass spectrometry (MS) lipidomic approaches represented by three analytical methods in terms of comprehensiveness, sample throughput, and validation results for the lipidomic analysis of biological samples represented by tumor tissue, surrounding normal tissue, plasma, and erythrocytes of kidney cancer patients. Methods are compared in one laboratory using the identical analytical protocol to ensure comparable conditions. Ultrahigh-performance liquid chromatography/MS (UHPLC/MS) method in hydrophilic interaction liquid chromatography mode and DI-MS method are used for this comparison as the most widely used methods for the lipidomic analysis together with ultrahigh-performance supercritical fluid chromatography/MS (UHPSFC/MS) method showing promising results in metabolomics analyses. The nontargeted analysis of pooled samples is performed using all tested methods and 610 lipid species within 23 lipid classes are identified. DI method provides the most comprehensive results due to identification of some polar lipid classes, which are not identified by UHPLC and UHPSFC methods. On the other hand, UHPSFC method provides an excellent sensitivity for less polar lipid classes and the highest sample throughput within 10min method time. The sample consumption of DI method is 125 times higher than for other methods, while only 40μL of organic solvent is used for one sample analysis compared to 3.5mL and 4.9mL in case of UHPLC and UHPSFC methods, respectively. Methods are validated for the quantitative lipidomic analysis of plasma samples with one internal standard for each lipid class. Results show applicability of all tested methods for the lipidomic analysis of biological samples depending on the analysis requirements

  4. Liquid chromatography tandem mass spectrometry determination of total budesonide levels in dog plasma after inhalation exposure.

    Science.gov (United States)

    Berg, Seija; Melamies, Marika; Rajamäki, Minna; Vainio, Outi; Peltonen, Kimmo

    2012-01-01

    A sensitive and selective method to quantify budesonide in dog plasma samples was developed and fully validated. Liquid-liquid extraction was followed by solid-phase extraction and liquid chromatography-tandem mass spectrometry with electrospray ionization. After reconstitution of the analytes in the mobile phase, samples were analysed by reversed-phase liquid chromatography with isocratic elution. d8-Budesonide was used as an internal standard, and characteristic transitions of d8-budesonide and budesonide were used for quantification. The method was validated with respect to selectivity, specificity, linearity, recovery, repeatability, reproducibility and limits of detection and quantification. The validated method was successfully applied to monitor the plasma levels of budesonide in dogs exposed to clinical doses of inhaled and intravenous drug.

  5. Determination of five antiarrhythmic drugs in human plasma by dispersive liquid-liquid microextraction and high-performance liquid chromatography.

    Science.gov (United States)

    Jouyban, Abolghasem; Sorouraddin, Mohammad Hossein; Farajzadeh, Mir Ali; Somi, Mohammad Hossein; Fazeli-Bakhtiyari, Rana

    2015-03-01

    A fast and sensitive high-performance liquid chromatography (HPLC) method with ultraviolet (UV) detection was developed and validated for the simultaneous quantitation of five antiarrhythmic drugs (metoprolol, propranolol, carvedilol, diltiazem, and verapamil) in human plasma samples. It involves dispersive liquid-liquid microextraction (DLLME) of the desired drugs from 660 µL plasma and separation using isocratic elution with UV detection at 200 nm. The complete separation of all analytes was achieved within 7 min. Acetonitrile (as disperser solvent) resulting from the protein precipitation procedure was mixed with 100 µL dichloromethane (as an extraction solvent) and rapidly injected into 5 mL aqueous solution (pH 11.5) containing 1% (w/v), NaCl. After centrifugation, the sedimented phase containing enriched analytes was collected and evaporated to dryness. The residue was re-dissolved in 50 µL de-ionized water (acidified to pH 3) and injected into the HPLC system for analysis. Under the optimal conditions, the enrichment factors and extraction recoveries ranged between 4.4-10.8 and 33-82%, respectively. The suggested method was linear (r(2) ≥0.997) over a dynamic range of 0.02-0.80 µg mL(-1) in plasma. The intra- and inter-days relative standard deviation (RSD%) and relative error (RE%) values of the method were below 20%, which shows good precision and accuracy. Finally, this method was applied to the analysis of real plasma samples obtained from the patients treated with these drugs. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Analysis of drugs of abuse in human plasma by dispersive liquid-liquid microextraction and high-performance liquid chromatography.

    Science.gov (United States)

    Fernández, P; Regenjo, M; Bermejo, A M; Fernández, A M; Lorenzo, R A; Carro, A M

    2015-04-01

    Opioids and cocaine are widely used at present, both for recreational purposes and as drugs of abuse. This raises the need to develop new analytical methods specifically designed for the simultaneous detection of several drugs of abuse in biological samples. In this work, dispersive liquid-liquid microextraction (DLLME) was assessed as a new sample treatment for the simultaneous extraction of morphine (MOR), 6-acetylmorphine (6AM), cocaine (COC), benzoylecgonine (BZE) and methadone (MET) from human plasma. Preliminary assays were done before developing an experimental design based on a Uniform Network Doehlert which allowed the optimum extraction conditions to be identified, namely: a volume of extractant solvent (chloroform) and dispersant solvent (acetonitrile) of 220 µl and 3.2 ml, respectively; 0.2 g of NaCl as a salting-out additive; pH 10.6 and ultrasound stirring for 3.5 min. The resulting extracts were analyzed by high-performance liquid chromatography with photodiode array detection (HPLC-PDA), using an XBridge® RP18 column (250 × 4.6 mm i.d., 5 µm particle size). Calibration graphs were linear over the concentration range 0.1-10 µg ml⁻¹, and detection limits ranged from 13.9 to 28.5 ng ml⁻¹. Precision calculated at three different concentration levels in plasma was included in the range 0.1-6.8% RSD. Recoveries of the five drugs were all higher than 84% on average. Finally the proposed method was successfully applied to 22 plasma samples from heroin, cocaine and/or methadone users, and the most frequently detected drug was benzoylecgonine, followed by methadone, cocaine and morphine. Copyright © 2014 John Wiley & Sons, Ltd.

  7. Determination of statin drugs in hospital effluent with dispersive liquid-liquid microextraction and quantification by liquid chromatography.

    Science.gov (United States)

    Martins, Ayrton F; Frank, Carla da S; Altissimo, Joseline; de Oliveira, Júlia A; da Silva, Daiane S; Reichert, Jaqueline F; Souza, Darliana M

    2017-08-24

    Statins are classified as being amongst the most prescribed agents for treating hypercholesterolaemia and preventing vascular diseases. In this study, a rapid and effective liquid chromatography method, assisted by diode array detection, was designed and validated for the simultaneous quantification of atorvastatin (ATO) and simvastatin (SIM) in hospital effluent samples. The solid phase extraction (SPE) of the analytes was optimized regarding sorbent material and pH, and the dispersive liquid-liquid microextraction (DLLME), in terms of pH, ionic strength, type and volume of extractor/dispersor solvents. The performance of both extraction procedures was evaluated in terms of linearity, quantification limits, accuracy (recovery %), precision and matrix effects for each analyte. The methods proved to be linear in the concentration range considered; the quantification limits were 0.45 µg L -1 for ATO and 0.75 µg L -1 for SIM; the matrix effect was almost absent in both methods and the average recoveries remained between 81.5-90.0%; and the RSD values were <20%. The validated methods were applied to the quantification of the statins in real samples of hospital effluent; the concentrations ranged from 18.8 µg L -1 to 35.3 µg L -1 for ATO, and from 30.3 µg L -1 to 38.5 µg L -1 for SIM. Since the calculated risk quotient was ≤192, the occurrence of ATO and SIM in hospital effluent poses a potential serious risk to human health and the aquatic ecosystem.

  8. Determination of denaturated proteins and biotoxins by on-line size-exclusion chromatography-digestion-liquid chromatography-electrospray mass spectrometry

    NARCIS (Netherlands)

    Carol, J.; Gorseling, M.C.J.K.; Jong, C.F. de; Lingeman, H.; Kientz, C.E.; Baar, B.L.M. van; Irth, H.

    2005-01-01

    A multidimensional analytical method for the rapid determination and identification of proteins has been developed. The method is based on the size-exclusion fractionation of protein-containing samples, subsequent on-line trypsin digestion and desalination, and reversed-phase high-performance liquid

  9. Liquid chromatography and supercritical fluid chromatography as alternative techniques to gas chromatography for the rapid screening of anabolic agents in urine.

    Science.gov (United States)

    Desfontaine, Vincent; Nováková, Lucie; Ponzetto, Federico; Nicoli, Raul; Saugy, Martial; Veuthey, Jean-Luc; Guillarme, Davy

    2016-06-17

    This work describes the development of two methods involving supported liquid extraction (SLE) sample treatment followed by ultra-high performance liquid chromatography or ultra-high performance supercritical fluid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS and UHPSFC-MS/MS) for the screening of 43 anabolic agents in human urine. After evaluating different stationary phases, a polar-embedded C18 and a diol columns were selected for UHPLC-MS/MS and UHPSFC-MS/MS, respectively. Sample preparation, mobile phases and MS conditions were also finely tuned to achieve highest selectivity, chromatographic resolution and sensitivity. Then, the performance of these two methods was compared to the reference routine procedure for steroid analyses in anti-doping laboratories, which combines liquid-liquid extraction (LLE) followed by gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). For this purpose, urine samples spiked with the compounds of interest at five different concentrations were analyzed using the three analytical platforms. The retention and selectivity of the three techniques were very different, ensuring a good complementarity. However, the two new methods displayed numerous advantages. The overall procedure was much faster thanks to high throughput SLE sample treatment using 48-well plates and faster chromatographic analysis. Moreover, the highest sensitivity was attained using UHPLC-MS/MS with 98% of the doping agents detected at the lowest concentration level (0.1ng/mL), against 76% for UHPSFC-MS/MS and only 14% for GC-MS/MS. Finally, the weakest matrix effects were obtained with UHPSFC-MS/MS with 76% of the analytes displaying relative matrix effect between -20 and 20%, while the GC-MS/MS reference method displayed very strong matrix effects (over 100%) for all of the anabolic agents. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, Tanja C. W.; Schierbeek, Henk; Houtekamer, Marco; van Engeland, Tom; Derrien, Delphine; Stal, Lucas J.; Boschker, Henricus T. S.

    2015-01-01

    We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of δ(13)C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although

  11. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, T.C.W.; Schierbeek, H.; Houtekamer, M.; van Engeland, T.; Derrien, D.; Stal, L.J.; Boschker, H.T.S.

    2015-01-01

    We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of d13C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although

  12. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, T.C.W.; Schierbeek, H.; Houtekamer, M.; van Engeland, T.; Derrien, D.; Stal, L.J.; Boschker, H.T.S.

    2015-01-01

    Rationale: We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of δ13C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence,

  13. High-performance liquid chromatography of human glycoprotein hormones.

    Science.gov (United States)

    Chlenov, M A; Kandyba, E I; Nagornaya, L V; Orlova, I L; Volgin, Y V

    1993-02-12

    The chromatographic behavior of the glycoprotein hormones from human pituitary glands and of placental origin [thyroid-stimulating hormone, luteinizing hormone and chorionic gonadotropin (CG)] was studied. It was shown that hydrophobic interaction chromatography on a microparticulate packing and anion-exchange HPLC can be applied for the purification of these hormones. Reversed-phase HPLC on wide-pore C4-bonded silica at neutral pH can be applied for the determination of the above hormones and for the isolation of pure CG and its subunits.

  14. Separation of hemagglutination-inhibiting immunoglobulin M antibody to rubella virus in human serum by high-performance liquid chromatography.

    OpenAIRE

    Kobayashi, N; Suzuki, M; Nakagawa, T; Matumoto, M

    1986-01-01

    High-performance liquid chromatography was successfully used to separate hemagglutination-inhibiting immunoglobulin M (IgM) rubella virus antibody from IgG rubella virus antibody in human serum. The fractionation by high-performance liquid chromatography was as effective as sucrose density gradient centrifugation in separating IgM antibody from IgG antibody.

  15. Application in pesticide analysis: Liquid chromatography - A review of the state of science for biomarker discovery and identification

    Science.gov (United States)

    Book Chapter 18, titled Application in pesticide analysis: Liquid chromatography - A review of the state of science for biomarker discovery and identification, will be published in the book titled High Performance Liquid Chromatography in Pesticide Residue Analysis (Part of the C...

  16. The analysis of aqueous mixtures using liquid chromatography-electrospray mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Steven [Iowa State Univ., Ames, IA (United States)

    1999-02-12

    The focus of this dissertation is the use of chromatographic methods coupled with electrospray mass spectrometry (ES-MS) for the determination of both organic and inorganic compounds in aqueous solutions. The combination of liquid chromatography (LC) methods and ES-MS offers one of the foremost methods for determining compounds in complex aqueous solutions. In this work, LC-ES-MS methods are devised using ion exclusion chromatography, reversed phase chromatography, and ion exchange chromatography, as well as capillary electrophoresis (CE). For an aqueous sample, these LC-ES-MS and CE-ES-MS techniques require no sample preparation or analyte derivatization, which makes it possible to observe a wide variety of analytes as they exist in solution. The majority of this work focuses on the use of LC-ES-MS for the determination of unknown products and intermediates formed during electrochemical incineration (ECI), an experimental waste remediation process. This report contains a general introduction to the project and the general conclusions. Four chapters have been removed for separate processing. Titles are: Chapter 2: Determination of small carboxylic acids by ion exclusion chromatography with electrospray mass spectrometry; Chapter 3: Electrochemical incineration of benzoquinone in aqueous media using a quaternary metal oxide electrode in the absence of a soluble supporting electrolyte; Chapter 4: The determination of electrochemical incineration products of 4-chlorophenol by liquid chromatography-electrospray mass spectrometry; and Chapter 5: Determination of small carboxylic acids by capillary electrophoresis with electrospray mass spectrometry.

  17. Resolution of RNA using high-performance liquid chromatography

    NARCIS (Netherlands)

    Mclaughlin, L.W.; Bischoff, Rainer

    1987-01-01

    High-performance liquid chromatographic techniques can be very effective for the resolution and isolation of nucleic acids. The characteristic ionic (phosphodiesters) and hydrophobic (nucleobases) properties of RNAs can be exploited for their separation. In this respect anion-exchange and

  18. Buffer-Free High Performance Liquid Chromatography Method for ...

    African Journals Online (AJOL)

    Purpose: To develop and validate a simple, economical and reproducible high performance liquid chromatographic (HPLC) method for the determination of theophylline in pharmaceutical dosage forms. Method: Caffeine was used as the internal standard and reversed phase C-18 column was used to elute the drug and ...

  19. Determination of ribavirin in human serum using liquid chromatography tandem mass spectrometry

    NARCIS (Netherlands)

    van der Lijke, H.; Alffenaar, J.-W. C.; Kok, W.Th.; Greijdanus, B.; Uges, D.R.A.

    2012-01-01

    A method has been developed for the determination of ribavirin in human serum for therapeutic drug monitoring purposes, using liquid chromatography electrospray ionization mass spectrometry. Separation was obtained with a mobile phase gradient starting and ending in 100% aqueous conditions using a

  20. Determination of low molecular weight thiols using monobromobimane fluorescent labeling and high-performance liquid chromatography

    Science.gov (United States)

    Fahey, Robert C.; Newton, Gerald L.

    1988-01-01

    Methods are described for the preparation and high-performance liquid chromatography (HPLC) analysis of monobromobimane derivatives of low molecular weight thiols in extracts of biological samples. Typical problems encountered in the development and application of these methods are discussed. Analysis of mung bean extract is used as an example.

  1. Sugar Determination in Foods with a Radially Compressed High Performance Liquid Chromatography Column.

    Science.gov (United States)

    Ondrus, Martin G.; And Others

    1983-01-01

    Advocates use of Waters Associates Radial Compression Separation System for high performance liquid chromatography. Discusses instrumentation and reagents, outlining procedure for analyzing various foods and discussing typical student data. Points out potential problems due to impurities and pump seal life. Suggests use of ribose as internal…

  2. Determination of Peroxide-Based Explosives Using Liquid Chromatography with On-Line Infrared Detection

    NARCIS (Netherlands)

    Schulte-Ladbeck, Rasmus; Edelmann, Andrea; Quintas, Guillermo; Lendl, Bernhard; Karst, U.

    2006-01-01

    A nondestructive analytical method for peroxide-based explosives determination in solid samples is described. Reversed-phase high-performance liquid chromatography in combination with on-line Fourier transform infrared (FT-IR) detection is used for the analysis of triacetonetriperoxide (TATP) and

  3. Simultaneous quantitative analysis of metabolites using ion-pair liquid chromatography-electrospray ionization mass spectrometry

    NARCIS (Netherlands)

    Coulier, L.; Bas, R.; Jespersen, S.; Verheij, E.; Werf, M.J. van der; Hankemeier, T.

    2006-01-01

    We have developed an analytical method, consisting of ion-pair liquid chromatography coupled to electrospray ionization mass spectrometry (IP-LC-ESI-MS), for the simultaneous quantitative analysis of several key classes of polar metabolites, like nucleotides, coenzyme A esters, sugar nucleotides,

  4. High-Performance Liquid Chromatography in the Undergraduate Chemical Engineering Laboratory

    Science.gov (United States)

    Frey, Douglas D.; Guo, Hui; Karnik, Nikhila

    2013-01-01

    This article describes the assembly of a simple, low-cost, high-performance liquid chromatography (HPLC) system and its use in the undergraduate chemical engineering laboratory course to perform simple experiments. By interpreting the results from these experiments students are able to gain significant experience in the general method of…

  5. Isotope Fractionation in Methane Reactions Studied by Gas Chromatography and Liquid Scintillation

    DEFF Research Database (Denmark)

    Andersen, Bertel Lohmann; Bidoglio, G.; Leip, A.

    1997-01-01

    Determination of C-14-marked methane by gas chromatography and liquid scintillation counting is shown to be useful in studies of isotope effects. Data on the specific activity is used to separate the contributions of (CH4)-C-14, and (CH4)-C-12 to the gas-chromatographic peak area. As an application...

  6. Improvement of recovery and repeatability in liquid chromatography-mass spectrometry analysis of peptides

    NARCIS (Netherlands)

    van Midwoud, Paul M.; Rieux, Laurent; Bischoff, Rainer; Verpoorte, Elisabeth; Niederlander, Harm A. G.

    2007-01-01

    Poor repeatability of peak areas is a problem frequently encountered in peptide analysis with nanoLiquid Chromatography coupled on-line with Mass Spectrometry (nanoLC-MS). As a result, quantitative analysis will be seriously hampered unless the observed variability can be corrected in some way.

  7. Serum Protein Profile Study of Clinical Samples Using High Performance Liquid Chromatography-Laser Induced Fluorescence

    DEFF Research Database (Denmark)

    Karemore, Gopal Raghunath; Ukendt, Sujatha; Rai, Lavanya

    2009-01-01

    The serum protein profiles of normal subjects, patients diagnosed with cervical cancer, and oral cancer were recorded using High Performance Liquid Chromatography combined with Laser Induced Fluorescence detection (HPLC-LIF). Serum protein profiles of the above three classes were tested for estab...

  8. Nitrate and nitrite content in bottled beverages by ion-pair high-performance liquid chromatography.

    Science.gov (United States)

    Song, Yang; Deng, Gui-Fang; Xu, Xiang-Rong; Chen, Yong-Hong; Chen, Feng; Li, Hua-Bin

    2013-01-01

    Nitrate and nitrite levels in six types of beverages--total of 292 individual samples from 73 brands (four bottles each)--from Guangzhou city in China were evaluated by ion-pair high-performance liquid chromatography. All samples contained nitrate. Nitrate and nitrite ranges were 0.43-46.08 and safety of Chinese bottled beverages.

  9. DETERMINATION OF CHLOROPHEONIS, NITROPHENOIS AND METHYLPHENOIS IN GROUND-WATER SAMPLES USING HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

    Science.gov (United States)

    A high performance liquid chromatography (HPLC) method was developed to quantitatively determine phenolic compounds and their isomers in aqueous samples. The HPLC method can analyze a mixture of 15 contaminants in the same analytical run with an analysis time of 25 minutes. The...

  10. High Performance Liquid Chromatography of Some Analgesic Compounds: An Instrumental Analysis Experiment.

    Science.gov (United States)

    Haddad, Paul; And Others

    1983-01-01

    Background information, procedures, and results are provided for an experiment demonstrating techniques of solvent selection, gradient elution, pH control, and ion-pairing in the analysis of an analgesic mixture using reversed-phase liquid chromatography on an octadecylsilane column. Although developed using sophisticated/expensive equipment, less…

  11. DETERMINATION OF CHLOROPHENOLS, NITROPHENOLS, AND METHYLPHENOLS IN GROUND-WATER SAMPLES USING HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

    Science.gov (United States)

    A high performance liquid chromatography (HPLC) method was developed to quantitatively determine phenolic compounds and their isomers in aqueous samples. The HPLC method can analyze a mixture of 15 contaminants in the same analytical run with an analysis time of 25 minutes. The...

  12. Coupling nanoliter high-performance liquid chromatography to inductively coupled plasma mass spectrometry for arsenic speciation.

    Science.gov (United States)

    Cheng, Heyong; Shen, Lihuan; Liu, Jinhua; Xu, Zigang; Wang, Yuanchao

    2018-04-01

    Nanoliter high-performance liquid chromatography shows low consumption of solvents and samples, offering one of the best choices for arsenic speciation in precious samples in combination with inuctively coupled plasma mass spectrometry. A systematic investigation on coupling nanoliter high-performance liquid chromatography to inductively coupled plasma mass spectrometry from instrument design to injected sample volume and mobile phase was performed in this study. Nanoflow mobile phase was delivered by flow splitting using a conventional high-pressure pump with reuse of mobile phase waste. Dead volume was minimized to 60 nL for the sheathless interface based on the previously developed nanonebulizer. Capillary columns for nanoliter high-performance liquid chromatography were found to be sensitive to sample loading volume. An apparent difference was also found between the mobile phases for nanoliter and conventional high-performance liquid chromatography. Baseline separation of arsenite, arsenate, monomethylarsenic, and dimethylarsenic was achieved within 11 min on a 15 cm C 18 capillary column and within 12 min on a 25 cm strong anion exchange column. Detection limits of 0.9-1.8 μg/L were obtained with precisions variable in the range of 1.6-4.2%. A good agreement between determined and certified values of a certified reference material of human urine (GBW 09115) validated its accuracy along with good recoveries (87-102%). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Simultaneous determination of seven flavonoids in Epimedium by liquid chromatography-tandem mass spectrometry method

    Institute of Scientific and Technical Information of China (English)

    Cai Sheng Wu; Bao Lin Guo; Yu Xin Sheng; Jin Lan Zhang

    2008-01-01

    In this paper, a sensitive and specific liquid chromatography-electrospray ionisation-mass spectrometry (LC-ESI-MS) method has been developed and validated for the identification and determination of seven flavonoids, namely epimedin A, epimedin B, epimedin C, icariin, sagittatoside B, 2"-0-rhamnosyl icariside II, and baohuoside I in Epimedium from different sources.

  14. High-performance liquid chromatography determination of dapsone, monoacetyldapsone, and pyrimethamine in filter paper blood spots

    DEFF Research Database (Denmark)

    Rønn, A M; Lemnge, M M; Angelo, H R

    1995-01-01

    A high-performance liquid chromatography method for the simultaneous analysis of dapsone (DDS), the major metabolite of DDS, monoacetyldapsone (MADDS), and pyrimethamine (PYR) was modified for capillary blood samples obtained by finger prick and dried on filter paper. Limit of quantitation using...

  15. Alternative sample-introduction technique to avoid breakthrough in gradient-elution liquid chromatography of polymers

    NARCIS (Netherlands)

    Reingruber, E.; Bedani, F.; Buchberger, W.; Schoenmakers, P.

    2010-01-01

    Gradient-elution liquid chromatography (GELC) is a powerful tool for the characterization of synthetic polymers. However, gradient-elution chromatograms often suffer from breakthrough phenomena. Breakthrough can be averted by using a sample solvent as weak as the mobile phase. However, this approach

  16. Determination of organophosphorus acids by thermo-spray liquid chromatography-mass spectrometry

    NARCIS (Netherlands)

    Wils, E.R.J.; Hulst, A.G.

    1988-01-01

    The determination of thirteen organophosphorus acids, hydrolysis products of nerve agents and pesticides, by a combination of ion-pair liquid chromatography on a reversed-phase C18 column and thermospray mass spectrometry was investigated. Ammonium acetate and three tetraalkylammonium salts with

  17. Novel approach to determine ghrelin analogs by liquid chromatography with mass spectrometry using a monolithic column

    Czech Academy of Sciences Publication Activity Database

    Zemenová, Jana; Sýkora, D.; Adámková, H.; Maletínská, Lenka; Elbert, Tomáš; Marek, Aleš; Blechová, Miroslava

    2017-01-01

    Roč. 40, č. 5 (2017), s. 1032-1039 ISSN 1615-9306 Institutional support: RVO:61388963 Keywords : enzyme-linked immunosorbent assay * ghrelin * lipopeptides * liquid chromatography mass spectrometry * monolithic columns Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Analytical chemistry Impact factor: 2.557, year: 2016

  18. Deformation and degradation of polymers in ultra-high-pressure liquid chromatography

    NARCIS (Netherlands)

    Uliyanchenko, E.; van der Wal, S.; Schoenmakers, P.J.

    2011-01-01

    Ultra-high-pressure liquid chromatography (UHPLC) using columns packed with sub-2 μm particles has great potential for separations of many types of complex samples, including polymers. However, the application of UHPLC for the analysis of polymers meets some fundamental obstacles. Small particles

  19. Extraction and Purification of Glucoraphanin by Preparative High-Performance Liquid Chromatography (HPLC)

    Science.gov (United States)

    Lee, Iris; Boyce, Mary C.

    2011-01-01

    A student activity that focuses on the isolation of glucoraphanin from broccoli using preparative high-performance liquid chromatography (HPLC) is presented here. Glucoraphanin is a glucosinolate, whose byproducts are known to possess anticancer properties. It is present naturally at high levels in broccoli and other "Brassica" vegetables. This…

  20. Analysis of Currently Available Analgesic Tablets by Modern Liquid Chromatography: An Undergraduate Laboratory Introduction to HPLC.

    Science.gov (United States)

    Kagel, R. A.; Farwell, S. O.

    1983-01-01

    Background information, procedures, and results, are provided for an undergraduate experiment in which analgesic tablets are analyzed using liquid chromatography. The experiment, an improved, modified version of the Waters Associates Inc. experiment, is simple to prepare, requiring little glassware and minimal sample manipulation by students. (JN)

  1. Characterization of typical chemical background interferences in atmospheric pressure ionization liquid chromatography-mass spectrometry

    NARCIS (Netherlands)

    Guo, Xinghua; Bruins, Andries P.; Covey, Thomas R.

    2006-01-01

    The structures and origins of typical chemical background noise ions in positive atmospheric pressure ionization liquid chromatography/mass spectrometry (API LC/MS) are investigated and summarized in this study. This was done by classifying chemical background ions using precursor and product ion

  2. An Advanced, Interactive, High-Performance Liquid Chromatography Simulator and Instructor Resources

    Science.gov (United States)

    Boswell, Paul G.; Stoll, Dwight R.; Carr, Peter W.; Nagel, Megan L.; Vitha, Mark F.; Mabbott, Gary A.

    2013-01-01

    High-performance liquid chromatography (HPLC) simulation software has long been recognized as an effective educational tool, yet many of the existing HPLC simulators are either too expensive, outdated, or lack many important features necessary to make them widely useful for educational purposes. Here, a free, open-source HPLC simulator is…

  3. Simulated Moving Bed Chromatography: Separation and Recovery of Sugars and Ionic Liquid from Biomass Hydrolysates

    Science.gov (United States)

    Caes, Benjamin R.; Van Oosbree, Thomas R.; Lu, Fachuang; Ralph, John; Maravelias, Christos T.

    2015-01-01

    Simulated moving bed chromatography, a continuous separation method, enables the nearly quantitative recovery of sugar products and ionic liquid solvent from chemical hydrolysates of biomass. The ensuing sugars support microbial growth, and the residual lignin from the process is intact. PMID:23939991

  4. Determination of chlormequat in pears by liquid chromatography/mass spectrometry

    NARCIS (Netherlands)

    Mol, H.G.J.; Dam, R.C.J. van; Vreeken, R.J.; Steijger, O.M.

    2000-01-01

    A straightforward and reliable method was developed for the determination of chlormequat in pears by liquid chromatography/mass spectrometry (LC/MS). Water and methanol were compared as extraction solvents. Because no significant differences in extraction efficiency or repeatability were found,

  5. Assay of free urinary cortisol with inverted phase liquid chromatography and radiocompetition

    International Nuclear Information System (INIS)

    Franck, C.; Patricot, M.C.; Mathian, B.; Revol, A.

    1984-01-01

    The authors present an assay method for free urinary cortisol using inverted phase liquid chromatography for purification and radiocompetition for the assay. The usual values for adult men and women were established. The results of 150 routine assays were compared with those of 17 OHCS revealing the value of this assay [fr

  6. Analysis of 2-methylthio-derivatives of isoprenoid cytokinins by liquid chromatography-tandem mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Tarkowski, Petr; Václavíková, Kateřina; Novák, Ondřej; Pertry, I.; Hanuš, Jan; Whenham, R.; Vereecke, D.; Šebela, M.; Strnad, Miroslav

    2010-01-01

    Roč. 680, 1-2 (2010), s. 86-91 ISSN 0003-2670 R&D Projects: GA ČR GA301/08/1649 Institutional research plan: CEZ:AV0Z50380511 Keywords : Cytokinins * Rhodococcus fascians * High-performance liquid chromatography Subject RIV: CE - Biochemistry Impact factor: 4.310, year: 2010

  7. Monoliths in capillary electrochromatography and capillary liquid chromatography in conjunction with mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Moravcová, Dana; Rantamäki, A. H.; Duša, Filip; Wiedmer, S. K.

    2016-01-01

    Roč. 37, 7-8 (2016), s. 880-912 ISSN 0173-0835 Institutional support: RVO:68081715 Keywords : capillary electrochromatography * capillary liquid chromatography * mass spec- trometry * monolithic columns Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.744, year: 2016

  8. Separation and quantification of ropinirole and some impurities using capillary liquid chromatography

    NARCIS (Netherlands)

    Coufal, P.; Stulik, K.; Claessens, H.A.; Hardy, M.J.; Webb, M.

    1999-01-01

    Ropinirole, 4-[2-(dipropylamino)ethyl]-1,3-dihydro-2H-indol-2-one, is a potent anti-Parkinson’s disease drug developed by SmithKline Beecham Pharmaceuticals. Capillary liquid chromatography (CLC) was used for the separation and quantification of ropinirole and its five related impurities,

  9. An on-line high performance liquid chromatography-crocin bleaching assay for detection of antioxidants

    NARCIS (Netherlands)

    Bountagkidou, O.; Klift, van der E.J.C.; Tsimidou, M.Z.; Ordoudi, S.A.; Beek, van T.A.

    2012-01-01

    An on-line HPLC (high performance liquid chromatography) method for the rapid screening of individual antioxidants in mixtures was developed using crocin as a substrate (i.e. oxidation probe) and 2,2'-azobis(2-amidinopropane dihydrochloride (AAPH)) in phosphate buffer (pH 7.5) as a radical

  10. Separation of Poly(styrene-block-t-butyl methacrylate) Copolymers by Various Liquid Chromatography Techniques

    Science.gov (United States)

    Šmigovec Ljubič, Tina; Pahovnik, David; Žigon, Majda; Žagar, Ema

    2012-01-01

    The separation of a mixture of three poly(styrene-block-t-butyl methacrylate) copolymers (PS-b-PtBMA), consisting of polystyrene (PS) blocks of similar length and t-butyl methacrylate (PtBMA) blocks of different lengths, was performed using various chromatographic techniques, that is, a gradient liquid chromatography on reversed-phase (C18 and C8) and normal-phase columns, a liquid chromatography under critical conditions for polystyrene as well as a fully automated two-dimensional liquid chromatography that separates block copolymers by chemical composition in the first dimension and by molar mass in the second dimension. The results show that a partial separation of the mixture of PS-b-PtBMA copolymers can be achieved only by gradient liquid chromatography on reversed-phase columns. The coelution of the two block copolymers is ascribed to a much shorter PtBMA block length, compared to the PS block, as well as a small difference in the length of the PtBMA block in two of these copolymers, which was confirmed by SEC-MALS and NMR spectroscopy. PMID:22489207

  11. Column liquid chromatography- mass spectrometry: selected techniques in environmental applications for polar pesticides and related compounds.

    NARCIS (Netherlands)

    Slobodnik, J.; van Baar, B.L.M.; Brinkman, U.A.T.

    1995-01-01

    A review covering the field of environmental applications of liquid chromatography-mass spectrometry (LC-MS) is presented. Recent developments and advances are discussed with emphasis on the presently popular thermospray, particle beam and atmospheric pressure ionisation interfaces. Each interface

  12. Recent advances on multidimensional liquid chromatography–mass spectrometry for proteomics: From qualitative to quantitative analysis—A review

    International Nuclear Information System (INIS)

    Wu Qi; Yuan Huiming; Zhang Lihua; Zhang Yukui

    2012-01-01

    Highlights: ► We discuss progress of MDLC–MS systems in qualitative and quantitative proteomics. ► Both “Top-down” and “bottom-up” strategies are discussed in detail. ► On-line integrations of stable isotope labeling process are highlighted. ► This review gives insights into further directions for higher level integration. - Abstract: With the acceleration of proteome research, increasing attention has been paid to multidimensional liquid chromatography–mass spectrometry (MDLC–MS) due to its high peak capacity and separation efficiency. Recently, many efforts have been put to improve MDLC-based strategies including “top-down” and “bottom-up” to enable highly sensitive qualitative and quantitative analysis of proteins, as well as accelerate the whole analytical procedure. Integrated platforms with combination of sample pretreatment, multidimensional separations and identification were also developed to achieve high throughput and sensitive detection of proteomes, facilitating highly accurate and reproducible quantification. This review summarized the recent advances of such techniques and their applications in qualitative and quantitative analysis of proteomes.

  13. Characterization of goat colostrum oligosaccharides by nano-liquid chromatography on chip quadrupole time-of-flight mass spectrometry and hydrophilic interaction liquid chromatography-quadrupole mass spectrometry.

    Science.gov (United States)

    Martín-Ortiz, A; Salcedo, J; Barile, D; Bunyatratchata, A; Moreno, F J; Martin-García, I; Clemente, A; Sanz, M L; Ruiz-Matute, A I

    2016-01-08

    A detailed qualitative and quantitative characterization of goat colostrum oligosaccharides (GCO) has been carried out for the first time. Defatted and deproteinized colostrum samples, previously treated by size exclusion chromatography (SEC) to remove lactose, were analyzed by nanoflow liquid chromatography-quadrupole-time of flight mass spectrometry (Nano-LC-Chip-Q-TOF MS). Up to 78 oligosaccharides containing hexose, hexosamine, fucose, N-acetylneuraminic acid or N-glycolylneuraminic acid monomeric units were identified in the samples, some of them detected for the first time in goat colostra. As a second step, a hydrophilic interaction liquid chromatography coupled to mass spectrometry (HILIC-MS) methodology was developed for the separation and quantitation of the main GCO, both acidic and neutral carbohydrates. Among other experimental chromatographic conditions, mobile phase additives and column temperature were evaluated in terms of retention time, resolution, peak width and symmetry of target carbohydrates. Narrow peaks (wh: 0.2-0.6min) and good symmetry (As: 0.8-1.4) were obtained for GCO using an acetonitrile:water gradient with 0.1% ammonium hydroxide at 40°C. These conditions were selected to quantify the main oligosaccharides in goat colostrum samples. Values ranging from 140 to 315mgL(-1) for neutral oligosaccharides and from 83 to 251mgL(-1) for acidic oligosaccharides were found. The combination of both techniques resulted to be useful to achieve a comprehensive characterization of GCO. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Separation of carbohydrates using hydrophilic interaction liquid chromatography.

    Science.gov (United States)

    Fu, Qing; Liang, Tu; Li, Zhenyu; Xu, Xiaoyong; Ke, Yanxiong; Jin, Yu; Liang, Xinmiao

    2013-09-20

    A strategy was developed to rapidly evaluate chromatographic properties of hydrophilic interaction chromatography (HILIC) columns for separating carbohydrates. Seven HILIC columns (Silica, Diol, TSK Amide-80, XAmide, Click Maltose, Click β-CD, and Click TE-Cys columns) were evaluated by using three monosaccharide and seven disaccharides as probes. The influence of column temperature on the peak shape and tautomerization of carbohydrates, as well as column selectivity were investigated. The influence of surface charge property on the retention was also studied by using glucose, glucuronic acid, and glucosamine, which indicated that buffer salt concentration and pH value in mobile phase was necessary to control the ionic interactions between ionic carbohydrates and HILIC columns. According to evaluation results, the XAmide column was selected as an example to establish experimental schemes for separation of complex mixtures of oligosaccharide. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Review of in situ derivatization techniques for enhanced bioanalysis using liquid chromatography with mass spectrometry.

    Science.gov (United States)

    Baghdady, Yehia Z; Schug, Kevin A

    2016-01-01

    Accurate and specific analysis of target molecules in complex biological matrices remains a significant challenge, especially when ultra-trace detection limits are required. Liquid chromatography with mass spectrometry is often the method of choice for bioanalysis. Conventional sample preparation and clean-up methods prior to the analysis of biological fluids such as liquid-liquid extraction, solid-phase extraction, or protein precipitation are time-consuming, tedious, and can negatively affect target recovery and detection sensitivity. An alternative or complementary strategy is the use of an off-line or on-line in situ derivatization technique. In situ derivatization can be incorporated to directly derivatize target analytes in their native biological matrices, without any prior sample clean-up methods, to substitute or even enhance the extraction and preconcentration efficiency of these traditional sample preparation methods. Designed appropriately, it can reduce the number of sample preparation steps necessary prior to analysis. Moreover, in situ derivatization can be used to enhance the performance of the developed liquid chromatography with mass spectrometry-based bioanalysis methods regarding stability, chromatographic separation, selectivity, and ionization efficiency. This review presents an overview of the commonly used in situ derivatization techniques coupled to liquid chromatography with mass spectrometry-based bioanalysis to guide and to stimulate future research. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. High-performance liquid chromatography analysis methods developed for quantifying enzymatic esterification of flavonoids in ionic liquids

    DEFF Research Database (Denmark)

    Lue, Bena-Marie; Guo, Zheng; Xu, X.B.

    2008-01-01

    Methods using reversed-phase high-performance liquid chromatography (RP-HPLC) with ELSD were investigated to quantify enzymatic reactions of flavonoids with fatty acids in the presence of diverse room temperature ionic liquids (RTILs). A buffered salt (preferably triethylamine-acetate) was found...... essential for separation of flavonoids from strongly polar RTILs, whereby RTILs were generally visible as two major peaks identified based on an ion-pairing/exchanging hypothesis. C8 and C12 stationary phases were optimal while mobile phase pH (3-7) had only a minor influence on separation. The method...

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

    Science.gov (United States)

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

    2018-01-15

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

  18. Determination of Oxidized Phosphatidylcholines by Hydrophilic Interaction Liquid Chromatography Coupled to Fourier Transform Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Pia Sala

    2015-04-01

    Full Text Available A novel liquid chromatography-mass spectrometry (LC-MS approach for analysis of oxidized phosphatidylcholines by an Orbitrap Fourier Transform mass spectrometer in positive electrospray ionization (ESI coupled to hydrophilic interaction liquid chromatography (HILIC was developed. This method depends on three selectivity criteria for separation and identification: retention time, exact mass at a resolution of 100,000 and collision induced dissociation (CID fragment spectra in a linear ion trap. The process of chromatography development showed the best separation properties with a silica-based Kinetex column. This type of chromatography was able to separate all major lipid classes expected in mammalian samples, yielding increased sensitivity of oxidized phosphatidylcholines over reversed phase chromatography. Identification of molecular species was achieved by exact mass on intact molecular ions and CID tandem mass spectra containing characteristic fragments. Due to a lack of commercially available standards, method development was performed with copper induced oxidation products of palmitoyl-arachidonoyl-phosphatidylcholine, which resulted in a plethora of lipid species oxidized at the arachidonoyl moiety. Validation of the method was done with copper oxidized human low-density lipoprotein (LDL prepared by ultracentrifugation. In these LDL samples we could identify 46 oxidized molecular phosphatidylcholine species out of 99 possible candidates.

  19. Two-Dimensional Liquid Chromatography Analysis of Polystyrene/Polybutadiene Block Copolymers.

    Science.gov (United States)

    Lee, Sanghoon; Choi, Heejae; Chang, Taihyun; Staal, Bastiaan

    2018-05-15

    A detailed characterization of a commercial polystyrene/polybutadiene block copolymer material (Styrolux) was carried out using two-dimensional liquid chromatography (2D-LC). The Styrolux is prepared by statistical linking reaction of two different polystyrene- block-polybutadienyl anion precursors with a multivalent linking agent. Therefore, it is a mixture of a number of branched block copolymers different in molecular weight, composition, and chain architecture. While individual LC analysis, including size exclusion chromatography, interaction chromatography, or liquid chromatography at critical condition, is not good enough to resolve all the polymer species, 2D-LC separations coupling two chromatography methods were able to resolve all polymer species present in the sample; at least 13 block copolymer species and a homopolystyrene blended. Four different 2D-LC analyses combining a different pair of two LC methods provide their characteristic separation results. The separation characteristics of the 2D-LC separations are compared to elucidate the elution characteristics of the block copolymer species.

  20. The determination of antipyrine elimination in saliva by liquid chromatography.

    Science.gov (United States)

    Gartzke, J; Jäger, H

    1991-01-01

    A simple, fast and reliable liquid chromatographic method for the determination of antipyrine in saliva is described. The elimination of antipyrine is a good indicator for general evaluation of the liver function for dispositional purposes for example in occupational and environmental medicine. The described LC method was compared with a more extensive photometric procedure. The results obtained from both methods show very good correlation. Only one measurement is necessary to determine the antipyrine clearance. Furthermore the antipyrine dosage can be minimized, because of the sensitivity of the HPLC-method.

  1. Simultaneous determination of seven anticoagulant rodenticides in agricultural products by gel permeation chromatography and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Saito-Shida, Shizuka; Nemoto, Satoru; Matsuda, Rieko; Akiyama, Hiroshi

    2016-11-01

    A sensitive and reliable method for the simultaneous determination of hydroxycoumarin-type (brodifacoum, bromadiolone, coumatetralyl, and warfarin) and indandione-type (chlorophacinone, diphacinone, and pindone) rodenticides in agricultural products by gel permeation chromatography (GPC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed. The procedure involved extraction of the rodenticides from samples with acetone, followed by liquid-liquid partitioning with hexane/ethyl acetate (1:1, v/v) and 10% sodium chloride aqueous solution, then cleanup using GPC, and finally, analysis using LC-MS/MS. High recoveries from the GPC column were obtained for all rodenticides tested using a mobile phase of acetone/cyclohexane/triethylamine (400:1600:1, v/v/v). An ODS column, which contains low levels of metal impurities, gave satisfactory peak shapes for both hydroxycoumarin- and indandione-type rodenticides in the LC-MS/MS separation. The average recoveries of rodenticides from eight agricultural foods (apple, eggplant, cabbage, orange, potato, tomato, brown rice, and soybean) fortified at 0.0005-0.001 mg/kg ranged from 76 to 116%, except for bromadiolone in orange (53%) and diphacinone in soybean (54%), and the relative standard deviations ranged from 1 to 16%. The proposed method effectively removed interfering components, such as pigments and lipids, and showed high selectivity. In addition, the matrix effects were negligible for most of the rodenticide/food combinations. The results suggest that the proposed method is reliable and suitable for determining hydroxycoumarin- and indandione-type rodenticides in agricultural products.

  2. Combined high-performance liquid chromatography/32P-postlabeling assay of N7-methyldeoxyguanosine

    International Nuclear Information System (INIS)

    Shields, P.G.; Povey, A.C.; Wilson, V.L.; Weston, A.; Harris, C.C.

    1990-01-01

    A highly sensitive and specific assay for the detection of N7-methyl-2'-deoxyguanosine (N7methyldG) has been developed by combining high-performance liquid chromatography, 32 P-postlabeling, and nucleotide chromatography. Separation of normal nucleotides and adducts by high-performance liquid chromatography and then combining a portion of 2'-deoxyguanosine to the N7methyldG allows for quantitation using an internal standard. The directly determined molar ratio is not subject to errors in digestion, variable ATP-specific activity, or assumptions in relative adduct-labeling efficiency. The detection limit was one N7methyldG adduct in 10(7) unmodified 2'-deoxyguanosine bases. N7methyldG adducts have been detected in 5 human lung samples in which O6-methyl-2'-deoxyguanosine adducts had been previously determined. The mean ratio of N7methyldG to O6-methyl-2'-deoxyguanosine was determined to be approximately 10. The current assay complements the high-performance liquid chromatography/ 32 P-postlabeling assay for O6-methyl-2'-deoxyguanosine and increases the detection sensitivity of DNA methylated by exogenous alkylating agents

  3. Liquid chromatography-tandem mass spectrometric assay for the tyrosine kinase inhibitor afatinib in mouse plasma using salting-out liquid-liquid extraction

    NARCIS (Netherlands)

    Sparidans, Rolf W; van Hoppe, Stephanie; Rood, Johannes J M; Schinkel, Alfred H; Schellens, Jan H M; Beijnen, Jos H

    2016-01-01

    A quantitative bioanalytical liquid chromatography-tandem mass spectrometric (LC-MS/MS) assay for afatinib, an irreversible inhibitor of the ErbB (erythroblastic leukemia viral oncogene homolog) tyrosine kinase family, was developed and validated. Plasma samples were pre-treated using salting-out

  4. Sensitive determination of nitrophenol isomers by reverse-phase high-performance liquid chromatography in conjunction with liquid-liquid extraction

    Science.gov (United States)

    A method for the highly sensitive determination of 2-, 3- and 4- nitrophenols was developed using reverse-phase high-performance liquid chromatography (RP-HPLC) with a UV photodiode array detector. Using a reverse-phase column and 40% aqueous acetonitrile as an eluent (i.e. isocratic elution), the i...

  5. [Blood levels of homocysteine by high pressure liquid chromatography and comparison with two other techniques].

    Science.gov (United States)

    Ceppa, F; Drouillard, I; Chianea, D; Burnat, P; Perrier, F; Vaillant, C; El Jahiri, Y

    1999-01-01

    Cardio-vascular diseases are the most common cause of death in industrialized countries. A new marker has emerged among offending risk factors in the past few years: homocysteine. This sulphured amino-acid is an important intermediate in transsulphuration and remethylation reactions of methionine's metabolism. We proposed to evaluate a home made method of determination for this parameter by high performance liquid chromatography (HPLC) and to compare it to fluorescence polarization immunoassay technique (FPIA) and to gaz phase chromatography (CG-SM). This method associated with good sensibility and precision remain much less expensive than FPIA technique.

  6. Characterization of Extracellular Vesicles by Size-Exclusion High-Performance Liquid Chromatography (HPLC).

    Science.gov (United States)

    Huang, Tao; He, Jiang

    2017-01-01

    Extracellular vesicles (EVs) have recently attracted substantial attention due to the potential diagnostic and therapeutic relevance. Although a variety of techniques have been used to isolate and analyze EVs, it is still far away from satisfaction. Size-exclusion chromatography (SEC), which separates subjects by size, has been widely applied in protein purification and analysis. The purpose of this chapter is to show the applications of size-exclusion high-performance liquid chromatography (HPLC) as methods for EV characterization of impurities or contaminants of small size, and thus for quality assay for the purity of the samples of EVs.

  7. Nanoparticle Analysis by Online Comprehensive Two-Dimensional Liquid Chromatography combining Hydrodynamic Chromatography and Size-Exclusion Chromatography with Intermediate Sample Transformation

    Science.gov (United States)

    2017-01-01

    Polymeric nanoparticles have become indispensable in modern society with a wide array of applications ranging from waterborne coatings to drug-carrier-delivery systems. While a large range of techniques exist to determine a multitude of properties of these particles, relating physicochemical properties of the particle to the chemical structure of the intrinsic polymers is still challenging. A novel, highly orthogonal separation system based on comprehensive two-dimensional liquid chromatography (LC × LC) has been developed. The system combines hydrodynamic chromatography (HDC) in the first-dimension to separate the particles based on their size, with ultrahigh-performance size-exclusion chromatography (SEC) in the second dimension to separate the constituting polymer molecules according to their hydrodynamic radius for each of 80 to 100 separated fractions. A chip-based mixer is incorporated to transform the sample by dissolving the separated nanoparticles from the first-dimension online in tetrahydrofuran. The polymer bands are then focused using stationary-phase-assisted modulation to enhance sensitivity, and the water from the first-dimension eluent is largely eliminated to allow interaction-free SEC. Using the developed system, the combined two-dimensional distribution of the particle-size and the molecular-size of a mixture of various polystyrene (PS) and polyacrylate (PACR) nanoparticles has been obtained within 60 min. PMID:28745485

  8. Determination of pyrazinamide in human by high performance liquid chromatography.

    Directory of Open Access Journals (Sweden)

    Revankar S

    1994-01-01

    Full Text Available A facile and sensitive high performance liquid chromatographic (HPLC technique has been developed for the determination pyrazinamide (PZA in human plasma. Nicotinamide(NIA is used as internal standard(IS. Plasma is deproteinized with 0.7 M perchloric acid; clear supernatant is neutralized with 1M NaOH and injected onto HPLC. The separation of pyrazinamide and the internal standard is carried out on a Supelco LC-18 (DB column with a basic mobile phase. Pyrazinoic acid, the major metabolite, other anti-tuberculous drugs and endogenous components do not interfere with measurement of pyrazinamide. The limit of detection of pyrazinamide with this method is 0.2 mg/0.2 ml plasma (CV 8.2%.

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

    Science.gov (United States)

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

    2016-06-05

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

  10. Development and evaluation of a liquid chromatography tandem mass spectrometry method for simultaneous determination of salivary melatonin, cortisol and testosterone

    DEFF Research Database (Denmark)

    Jensen, Marie Aarrebo; Hansen, Åse Marie; Abrahamsson, Peter

    2011-01-01

    saliva. We used liquid-liquid extraction (LLE) followed by liquid chromatography coupled to electrospray tandem mass spectrometry (LC-ESI-MS/MS) recorded in positive ion mode. Saliva samples were collected by spitting directly into tubes and 250 µL were used for analysis. The limits of detection were 4...

  11. [Separation and purification of the components in Trachelospermum jasminoides by two dimensional hydrophilic interaction liquid chromatography- reversed-phase liquid chromatography].

    Science.gov (United States)

    Jia, Youmei; Cai, Jianfeng; Xin, Huaxia; Feng, Jiatao; Fu, Yanhui; Fu, Qing; Jin, Yu

    2017-06-08

    A preparative two dimensional hydrophilic interaction liquid chromatography/reversed-phase liquid chromatography (Pre-2D-HILIC/RPLC) method was established to separate and purify the components in Trachelospermum jasminoides . The pigments and strongly polar components were removed from the crude extract after the active carbon decolorization and solid phase extraction processes. A Click XIon column (250 mm×20 mm, 10 μm) was selected as stationary phase and water-acetonitrile as mobile phases in the first dimensional HILIC. Finally, 15 fractions were collected under UV-triggered mode. In the second dimensional RPLC, a C18 column (250 mm×20 mm, 5 μm) was selected and water-acetonitrile was used as mobile phases. As a result, 14 compounds with high purity were obtained, which were further identified by mass spectrometry (MS) and nuclear magnetic resonance (NMR). Finally, 11 lignan compounds and three flavonoid compounds were obtained. The method has a good orthogonality, and can improve the resolution and the peak capacity. It is significant for the separation of complex components from Trachelospermum jasminoides .

  12. Chemical fingerprint of Ganmaoling granule by double-wavelength ultra high performance liquid chromatography and ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Lou, Qiong; Ye, Xiaolan; Zhou, Yingyi; Li, Hua; Song, Fenyun

    2015-06-01

    A method incorporating double-wavelength ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry was developed for the investigation of the chemical fingerprint of Ganmaoling granule. The chromatographic separations were performed on an ACQUITY UPLC HSS C18 column (2.1 × 50 mm, 1.8 μm) at 30°C using gradient elution with water/formic acid (1%) and acetonitrile at a flow rate of 0.4 mL/min. A total of 11 chemical constituents of Ganmaoling granule were identified from their molecular weight, UV spectra, tandem mass spectrometry data, and retention behavior by comparing the results with those of the reference standards or literature. And 25 peaks were selected as the common peaks for fingerprint analysis to evaluate the similarities among 25 batches of Ganmaoling granule. The results of principal component analysis and orthogonal projection to latent structures discriminant analysis showed that the important chemical markers that could distinguish the different batches were revealed as 4,5-di-O-caffeoylquinic acid, 3,5-di-O-caffeoylquinic acid, and 4-O-caffeoylquinic acid. This is the first report of the ultra high performance liquid chromatography chemical fingerprint and component identification of Ganmaoling granule, which could lay a foundation for further studies of Ganmaoling granule. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Determination of chloroacetanilide herbicide metabolites in water using high-performance liquid chromatography-diode array detection and high-performance liquid chromatography/mass spectrometry

    Science.gov (United States)

    Hostetler, K.A.; Thurman, E.M.

    2000-01-01

    Analytical methods using high-performance liquid chromatography-diode array detection (HPLC-DAD) and high-performance liquid chromatography/mass spectrometry (HPLC/MS) were developed for the analysis of the following chloroacetanilide herbicide metabolites in water: alachlor ethanesulfonic acid (ESA); alachlor oxanilic acid; acetochlor ESA; acetochlor oxanilic acid; metolachlor ESA; and metolachlor oxanilic acid. Good precision and accuracy were demonstrated for both the HPLC-DAD and HPLC/MS methods in reagent water, surface water, and ground water. The average HPLC-DAD recoveries of the chloroacetanilide herbicide metabolites from water samples spiked at 0.25, 0.5 and 2.0 ??g/l ranged from 84 to 112%, with relative standard deviations of 18% or less. The average HPLC/MS recoveries of the metabolites from water samples spiked at 0.05, 0.2 and 2.0 ??g/l ranged from 81 to 118%, with relative standard deviations of 20% or less. The limit of quantitation (LOQ) for all metabolites using the HPLC-DAD method was 0.20 ??g/l, whereas the LOQ using the HPLC/MS method was at 0.05 ??g/l. These metabolite-determination methods are valuable for acquiring information about water quality and the fate and transport of the parent chloroacetanilide herbicides in water. Copyright (C) 2000 Elsevier Science B.V.

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

    Directory of Open Access Journals (Sweden)

    Jean Wan Hong Yong

    2017-03-01

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

  15. On-line comprehensive two-dimensional normal-phase liquid chromatography × reversed-phase liquid chromatography for preparative isolation of Peucedanum praeruptorum.

    Science.gov (United States)

    Wang, Xin-Yuan; Li, Jia-Fu; Jian, Ya-Mei; Wu, Zhen; Fang, Mei-Juan; Qiu, Ying-Kun

    2015-03-27

    A new on-line comprehensive preparative two-dimensional normal-phase liquid chromatography × reversed-phase liquid chromatography (2D NPLC × RPLC) system was developed for the separation of complicated natural products. It was based on the use of a silica gel packed medium-pressure column as the first dimension and an ODS preparative HPLC column as the second dimension. The two dimensions were connected with normal-phase (NP) and reversed-phase (RP) enrichment units, involving a newly developed airflow assisted adsorption (AAA) technique. The instrument operation and the performance of this NPLC × RPLC separation method were illustrated by gram-scale isolation of ethanol extract from the roots of Peucedanum praeruptorum. In total, 19 compounds with high purity were obtained via automated multi-step preparative separation in a short period of time using this system, and their structures were comprehensively characterized by ESI-MS, (1)H NMR, and (13)C NMR. Including two new compounds, five isomers in two groups with identical HPLC and TLC retention values were also obtained and identified by 1D NMR and 2D NMR. This is the first report of an NPLC × RPLC system successfully applied in an on-line preparative process. This system not only solved the interfacing problem of mobile-phase immiscibility caused by NP and RP separation, it also exhibited apparent advantages in separation efficiency and sample treatment capacity compared with conventional methods. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Low-level flow counting of liquid chromatography column eluates

    International Nuclear Information System (INIS)

    Harding, N.G.L.; Farid, Y.; Stewart, M.J.

    1982-01-01

    The principal parameters which determine the operation of a high-resolution, high-sensitivity radioactive flow monitor are described: a) Sample preparation to ensure adequate recovery of radiolabelled sample, metabolites and internal standard. b) The instrument background count rate, when no sample or radiolabel is present in the flow cell, is a function of shielding and a reduction in noise obtained with a coincidence time below one microsecond. c) The minimum detectable amount of label depends upon the machine background, HPLC eluent and scintillator flow, whether or not packed flow cells are used, flow cell geometry, and the scintillator used. d) Three types of flow cell have been designed to cover the majority of HPLC and isotope applications. e) The performance of solid and liquid scintillators. It is shown that an instrument has been designed taking account of these parameters. The resulting design satisfies present high sensitivity counting requirements and maintains the resolution of current HPLC procedures when detection is by simultaneous flow radioassay and by optical methods. (orig.)

  17. Determination of Finasteride in Tablets by High Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    K. Basavaiah

    2007-01-01

    Full Text Available A rapid, highly sensitive high performance liquid chromatographic method has been developed for the determination of finasteride(FNS in bulk drug and in tablets. FNS was eluted from a ODS C18 reversed phase column at laboratory temperature (30 ± 2°C with a mobile phase consisting of methanol and water (80+20 at a flow rate of 1 mL min-1 with UV detection at 225 nm. The retention time was ∼ 6.1 min and each analysis took not more than 10 min. Quantitation was achieved by measurement of peak area without using any internal standard. Calibration graph was linear from 2.0 to 30 μg mL-1 with limits of detection (LOD and quantification (LOQ being 0.2 and 0.6 μg mL-1, respectively. The method was validated according to the current ICH guidelines. Within-day co efficients of variation (CV ranged from 0.31 to 0.69% and between-day CV were in the range 1.2-3.2%. Recovery of FNS from the pharmaceutical dosage forms ranged from 97.89 – 102.9 with CV of 1.41-4.13%. The developed method was compared with the official method for FNS determination in its tablet forms.

  18. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Column liquid chromatography applied to concentrating, separating, and determining platinum metals

    International Nuclear Information System (INIS)

    Alimarin, I.P.; Basova, E.M.; Bol'shova, T.A.; Ivanov, V.M.

    1986-01-01

    The present survey deals with high-performance liquid chromatography (HPLC) in relation to the chromatographic behavior of the platinum metals, including separation and determination. The data shows that HPLC is the most promising and effective method of separating metals, including platinum ones. The method provides efficient separation of microgram amoounts of mixtures with a resolving power 3-20 times that of thin-layer chromatography. It is shown that the most promising line of advance in HPLC for inorganic systems lies in the separation and determination of metals as chelates by absorption or ion-pair chromatography. Examples of using HPLC for determining noble metals in particular cases indicate that the metrological characteristics are favorable

  20. Determination of oxyfluorfen herbicide and oxyfluorfen amine residues in garbanzo beans by liquid chromatography.

    Science.gov (United States)

    Zhou, M; Miles, C J

    1991-01-01

    Oxyfluorfen and oxyfluorfen amine were determined by liquid chromatography (LC) with ultraviolet (UV) and photoconductivity detection (PCD). A simple extraction procedure acceptably recovered both analytes from garbanzo beans over a wide range of fortifications (0.05 to 20 ppm) (83 +/- 4 for oxyfluorfen; 85 +/- 4 for oxyfluorfen amine). Percent recoveries decreased slightly as the fortification level decreased. Both analytes could be determined simultaneously at a concentration greater than 0.2 ppm in garbanzo beans. Detection limits were 3 ng for oxyfluorfen and 100 ng for oxyfluorfen amine using LC/UV, and 12 ng for both oxyfluorfen and oxyfluorfen amine with LC/PCD. Different knitted reaction coils and photoreactors were evaluated. Photoproduct yields and identification were determined by ion chromatography. The LC/PCD method measures oxyfluorfen and oxyfluorfen amine separately and has a shorter analysis time, while the standard method using gas chromatography measures total residues and is more sensitive.

  1. Phytochemical Profile of Erythrina variegata by Using High-Performance Liquid Chromatography and Gas Chromatography-Mass Spectroscopy Analyses.

    Science.gov (United States)

    Muthukrishnan, Suriyavathana; Palanisamy, Subha; Subramanian, Senthilkumar; Selvaraj, Sumathi; Mari, Kavitha Rani; Kuppulingam, Ramalingam

    2016-08-01

    Natural products derived from plant sources have been utilized to treat patients with numerous diseases. The phytochemical constituents present in ethanolic leaf extract of Erythrina variegata (ELEV) were identified by using high-performance liquid chromatography (HPLC) and gas chromatography-mass spectroscopy (GC-MS) analyses. Shade dried leaves were powdered and extracted with ethanol for analyses through HPLC to identify selected flavonoids and through GC-MS to identify other molecules. The HPLC analysis of ELEV showed the presence of gallic and caffeic acids as the major components at concentrations of 2.0 ppm and 0.1 ppm, respectively, as well as other components. GC-MS analysis revealed the presence of 3-eicosyne; 3,7,11,15-tetramethyl-2-hexadecen-1-ol; butanoic acid, 3-methyl-3,7-dimethyl-6-octenyl ester; phytol; 1,2-benzenedicarboxylic acid, diundecyl ester; 1-octanol, 2-butyl-; squalene; and 2H-pyran, 2-(7-heptadecynyloxy) tetrahydro-derivative. Because pharmacopuncture is a new evolving natural mode that uses herbal extracts for treating patients with various ailments with minimum pain and maximum effect, the results of this study are particularly important and show that ELEV possesses a wide range of phytochemical constituents, as indicated above, as effective active principle molecules that can be used individually or in combination to treat patients with various diseases. Copyright © 2016. Published by Elsevier B.V.

  2. Gas chromatography-mass spectrometry and high-performance liquid chromatography-diode array detection for dating of paper ink.

    Science.gov (United States)

    Díaz-Santana, Oscar; Vega-Moreno, Daura; Conde-Hardisson, Francisco

    2017-09-15

    An extraction and determination method is shown for the analysis of dyes and solvents present in two types of ballpoint pen inks that are deposited onto paper. Ink extracts are analysed using a combination of gas chromatography with mass spectrometry (GC-MS), and high-pressure liquid chromatography with photodiode array detection (HPLC-DAD), within a single sample extraction procedure. Seventeen solvents and thirteen dyes contained in two Montblanc ® inks (black and blue) were monitored for 45 months at monthly intervals, in order to determine variations in the concentrations of the compounds over time. We also studied the relative variations between different compounds and the generation of degradation products such as phenol. The concentration data obtained from these compounds during their exposure have been analysed and a multiple regression model is developed for each ink type that allows an estimate of the exposure time of the ink on paper with a maximum error of between 4 and 7 months. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Pressurized planar electrochromatography, high-performance thin-layer chromatography and high-performance liquid chromatography--comparison of performance.

    Science.gov (United States)

    Płocharz, Paweł; Klimek-Turek, Anna; Dzido, Tadeusz H

    2010-07-16

    Kinetic performance, measured by plate height, of High-Performance Thin-Layer Chromatography (HPTLC), High-Performance Liquid Chromatography (HPLC) and Pressurized Planar Electrochromatography (PPEC) was compared for the systems with adsorbent of the HPTLC RP18W plate from Merck as the stationary phase and the mobile phase composed of acetonitrile and buffer solution. The HPLC column was packed with the adsorbent, which was scrapped from the chromatographic plate mentioned. An additional HPLC column was also packed with adsorbent of 5 microm particle diameter, C18 type silica based (LiChrosorb RP-18 from Merck). The dependence of plate height of both HPLC and PPEC separating systems on flow velocity of the mobile phase and on migration distance of the mobile phase in TLC system was presented applying test solute (prednisolone succinate). The highest performance, amongst systems investigated, was obtained for the PPEC system. The separation efficiency of the systems investigated in the paper was additionally confirmed by the separation of test component mixture composed of six hormones. 2010 Elsevier B.V. All rights reserved.

  4. Simultaneous achiral-chiral analysis of pharmaceutical compounds using two-dimensional reversed phase liquid chromatography-supercritical fluid chromatography.

    Science.gov (United States)

    Venkatramani, C J; Al-Sayah, Mohammad; Li, Guannan; Goel, Meenakshi; Girotti, James; Zang, Lisa; Wigman, Larry; Yehl, Peter; Chetwyn, Nik

    2016-02-01

    A new interface was designed to enable the coupling of reversed phase liquid chromatography (RPLC) and supercritical fluid chromatography (SFC). This online two-dimensional chromatographic system utilizing RPLC in the first dimension and SFC in the second was developed to achieve simultaneous achiral and chiral analysis of pharmaceutical compounds. The interface consists of an eight-port, dual-position switching valve with small volume C-18 trapping columns. The peaks of interest eluting from the first RPLC dimension column were effectively focused as sharp concentration pulses on small volume C-18 trapping column/s and then injected onto the second dimension SFC column. The first dimension RPLC separation provides the achiral purity result, and the second dimension SFC separation provides the chiral purity result (enantiomeric excess). The results are quantitative enabling simultaneous achiral, chiral analysis of compounds. The interface design and proof of concept demonstration are presented. Additionally, comparative studies to conventional SFC and case studies of the applications of 2D LC-SFC in pharmaceutical analysis is presented. Copyright © 2015 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2017-05-15

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

  6. Clinical applications of fast liquid chromatography: a review on the analysis of cardiovascular drugs and their metabolites.

    Science.gov (United States)

    Baranowska, Irena; Magiera, Sylwia; Baranowski, Jacek

    2013-05-15

    One of the major challenges facing the medicine today is developing new therapies that enhance human health. To help address these challenges the utilization of analytical technologies and high-throughput automated platforms has been employed; in order to perform more experiments in a shorter time frame with increased data quality. In the last decade various analytical strategies have been established to enhance separation speed and efficiency in liquid chromatography applications. Liquid chromatography is an increasingly important tool for monitoring drugs and their metabolites. Furthermore, liquid chromatography has played an important role in pharmacokinetics and metabolism studies at these drug development stages since its introduction. This paper provides an overview of current trends in fast chromatography for the analysis of cardiovascular drugs and their metabolites in clinical applications. Current trends in fast liquid chromatographic separations involve monolith technologies, fused-core columns, high-temperature liquid chromatography (HTLC) and ultra-high performance liquid chromatography (UHPLC). The high specificity in combination with high sensitivity makes it an attractive complementary method to traditional methodology used for routine applications. The practical aspects of, recent developments in and the present status of fast chromatography for the analysis of biological fluids for therapeutic drug and metabolite monitoring, pharmacokinetic studies and bioequivalence studies are presented. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Current practice of liquid chromatography-mass spectrometry in metabolomics and metabonomics.

    Science.gov (United States)

    Gika, Helen G; Theodoridis, Georgios A; Plumb, Robert S; Wilson, Ian D

    2014-01-01

    Based on publication and citation numbers liquid chromatography (LC-MS) has become the major analytical technology in the field of global metabolite profiling. This dominance reflects significant investments from both the research community and instrument manufacturers. Here an overview of the approaches taken for LC-MS-based metabolomics research is given, describing critical steps in the realisation of such studies: study design and its needs, specific technological problems to be addressed and major obstacles in data treatment and biomarker identification. The current state of the art for LC-MS-based analysis in metabonomics/metabolomics is described including recent developments in liquid chromatography, mass spectrometry and data treatment as these are applied in metabolomics underlining the challenges, limitations and prospects for metabolomics research. Examples of the application of metabolite profiling in the life sciences focusing on disease biomarker discovery are highlighted. In addition, new developments and future prospects are described. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Molecular differences between deuterated and protonated polystyrenes using reversed-phase high-performance liquid chromatography.

    Science.gov (United States)

    Kayillo, Sindy; Gray, Michael J; Shalliker, R Andrew; Dennis, Gary R

    2005-05-06

    Isotopic substitution is a technique used to highlight particular bonds within a molecule for kinetic, spectroscopic and structure analysis. It is presumed that although some properties such as stretching frequencies will not be the same for substituted analogues, the chemical interactions will not vary appreciably as a function of labelling. Reversed-phase liquid chromatography has been used to demonstrate that there are significant differences between the chromatographic behaviour of a sequence of deuterated and protonated oligomeric polystyrenes. Two-dimensional reversed-phase liquid chromatography was used to show that even the diasteromers of the oligomers (n = 5) have retention mechanisms that are dependent on the subtle changes to the molecular conformation and electronic structure, which are a consequence of deuteration.

  9. Controlled crosslinking of trimethylolpropane trimethacrylate for preparation of organic monolithic columns for capillary liquid chromatography.

    Science.gov (United States)

    Gama, Mariana R; Aggarwal, Pankaj; Lee, Milton L; Bottoli, Carla B G

    2017-11-01

    Organic monolithic columns based on single crosslinking of trimethylolpropane trimethacrylate (TRIM) monomer were prepared in a single step by living/controlled free-radical polymerization. Full optimization of the preparation, such as using different percentages of TRIM and different amounts of radical promoter as well as various porogen solvents were explored. The resulting monolithic columns were characterized by scanning electronic microscopy and nitrogen sorption for structure morphology studies and surface area measurements, respectively. Using capillary liquid chromatography, 150 μm i.d. columns were applied to separate a mixture of small hydrophobic molecules. The results indicated that column performance is highly sensitive to the type and the amount of porogen solvents used in the polymerization mixture composition. Good resolution factors and methylene selectivity were obtained, indicating the promising potential of this material for capillary liquid chromatography separations. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    Science.gov (United States)

    Ruan, Chunqiang; Zhao, Xiang; Liu, Chenglan

    2015-09-01

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

  11. Polymer Analysis by Liquid Chromatography/Electrospray Ionization Time-of-Flight Mass Spectrometry.

    Science.gov (United States)

    Nielen, M W; Buijtenhuijs, F A

    1999-05-01

    Hyphenation of liquid chromatography (LC) techniques with electrospray ionization (ESI) orthogonal acceleration time-of-flight (oa-TOF) mass spectrometry (MS) provides both MS-based structural information and LC-based quantitative data in polymer analysis. In one experimental setup, three different LC modes are interfaced with MS:  size-exclusion chromatography (SEC/MS), gradient polymer elution chromatography (GPEC/MS), and liquid chromatography at the critical point of adsorption (LCCC/MS). In SEC/MS, both absolute mass calibration of the SEC column based on the polymer itself and determination of monomers and end groups from the mass spectra are achieved. GPEC/MS shows detailed chemical heterogeneity of the polymer and the chemical composition distribution within oligomer groups. In LCCC/MS, the retention behavior is primarily governed by chemical heterogeneities, such as different end group functionalities, and quantitative end group calculations can be easily made. The potential of these methods and the benefit of time-of-flight analyzers in polymer analysis are discussed using SEC/MS of a polydisperse poly(methyl methacrylate) sample, GPEC/MS of dipropoxylated bisphenol A/adipic acid polyester resin, LCCC/MS of alkylated poly(ethylene glycol), and LCCC/MS of terephthalic acid/neopentyl glycol polyester resin.

  12. Metabolite Extraction from Saccharomyces cerevisiae for Liquid Chromatography-Mass Spectrometry.

    Science.gov (United States)

    Rosebrock, Adam P; Caudy, Amy A

    2017-09-01

    Prior to mass spectrometric analysis, cellular small molecules must be extracted and separated from interfering components such as salts and culture medium. To ensure minimal perturbation of metabolism, yeast cells grown in liquid culture are rapidly harvested by filtration as described here. Simultaneous quenching of metabolism and extraction is afforded by immediate immersion in low-temperature organic solvent. Samples prepared using this method are suitable for a range of downstream liquid chromatography-mass spectrometry analyses and are stable in solvent for >1 yr at -80°C. © 2017 Cold Spring Harbor Laboratory Press.

  13. Determination of preservatives in cosmetics, cleaning agents and pharmaceuticals using fast liquid chromatography.

    Science.gov (United States)

    Baranowska, Irena; Wojciechowska, Iwona; Solarz, Natalia; Krutysza, Ewa

    2014-01-01

    This paper reports the development of a method for simultaneously determining five preservatives in cosmetics, cleaning agents and pharmaceuticals by fast liquid chromatography. Methylisothiazolinone, methylchloroisothiazolinone, benzyl alcohol, sodium benzoate and methylparaben were separated on a Chromolith Fast Gradient reversed-phase 18e column using gradient elution with acetonitrile and a 0.1% aqueous solution of formic acid, with a run time of 3 min. The preparation of solid and liquid samples included ultrasonic extraction with methanol with recoveries ranging from 69 to 119%. The developed method was used to analyze samples of cosmetics (66 samples), cleaning agents (five samples) and pharmaceutical industry products (17 samples).

  14. Identification and Quantitation of Asparagine and Citrulline Using High-Performance Liquid Chromatography (HPLC)

    OpenAIRE

    Bai, Cheng; Reilly, Charles C.; Wood, Bruce W.

    2007-01-01

    High-performance liquid chromatography (HPLC) analysis was used for identification of two problematic ureides, asparagine and citrulline. We report here a technique that takes advantage of the predictable delay in retention time of the co-asparagine/citrulline peak to enable both qualitative and quantitative analysis of asparagine and citrulline using the Platinum EPS reverse-phase C18 column (Alltech Associates). Asparagine alone is eluted earlier than citrulline alone, but when both of them...

  15. DETECTION AND QUANTIFICATION OF PHYTOCHEMICAL MARKERS OF Ilex paraguariensis BY LIQUID CHROMATOGRAPHY

    OpenAIRE

    Pinto,Rodrigo M. C.; Lemes,Bruna M.; Zielinski,Acácio A. F.; Klein,Traudi; Paula,Fernado de; Kist,Airton; Marques,Anna S. F.; Nogueira,Alessandro; Demiate,Ivo M.; Beltrame,Flávio L.

    2015-01-01

    Ilex paraguariensis (yerba-mate) is used as a beverage, and its extract requires adequate quality control methods in order to guarantee quality and safe use. Strategies to develop and optimize a chromatographic method to quantify theobromine, caffeine, and chlorogenic acid in I. paraguariensis extracts were evaluated by applying a quality by design (QbD) model and ultra high-performance liquid chromatography (UHPLC). The presence of these three phytochemical markers in the extracts was evalua...

  16. Simultaneous Determination of Four Preservatives in Foodstuffs by High Performance Liquid Chromatography

    OpenAIRE

    Mohammad Faraji; Farzaneh Rahbarzare

    2016-01-01

    Background and objectives:  High concentration of preservatives in food may result in gastrointestinal disturbances whereby some patients suffering from asthma, rhinitis, or urticaria. The aim of this study is the introduction and optimization a new method for simultaneous determination of four preservatives (SB, PS, MP, PP) in foodstuff by high performance liquid chromatography. Materials and methods: Important factors in extraction, separation and determination process were optimiz...

  17. Analysis of oak tannins by liquid chromatography-electrospray ionisation mass spectrometry.

    Science.gov (United States)

    Mämmelä, P; Savolainen, H; Lindroos, L; Kangas, J; Vartiainen, T

    2000-09-01

    Extractable tannins were analysed by liquid chromatography-electrospray ionisation mass spectrometry in two oak species, North American white oak (Quercus alba) and European red oak (Quercus robur). They mainly included various glucose gallic and ellagic acid esters. The structures were partially determined, and they included grandinin/roburin E, castalagin/vescalagin, gallic acid, valoneic acid bilactone, monogalloyl glucose, digalloyl glucose, trigalloyl glucose, ellagic acid rhamnose, quercitrin and ellagic acid.

  18. Core-Shell Columns in High-Performance Liquid Chromatography: Food Analysis Applications

    OpenAIRE

    Preti, Raffaella

    2016-01-01

    The increased separation efficiency provided by the new technology of column packed with core-shell particles in high-performance liquid chromatography (HPLC) has resulted in their widespread diffusion in several analytical fields: from pharmaceutical, biological, environmental, and toxicological. The present paper presents their most recent applications in food analysis. Their use has proved to be particularly advantageous for the determination of compounds at trace levels or when a large am...

  19. Enantioselective analysis of drugs: contributions of high-performance liquid chromatography and capillary electrophoresis

    OpenAIRE

    Bonato, Pierina Sueli; Jabor, Valquíria Aparecida Polisel; Gaitani, Cristiane Masetto de

    2005-01-01

    The demand for analytical methods suitable for accurate and reproducible determination of drug enantiomers has increased significantly in the last years. High-performance liquid chromatography (HPLC) using chiral stationary phases and capillary electrophoresis (CE) are the most important techniques used for this purpose. In this paper, the fundamental aspects of chiral separations using both techniques are presented. Some important aspects for the development of enantioselective methods, part...

  20. RECENT ADVANCES IN ULTRA-HIGH PERFORMANCE LIQUID CHROMATOGRAPHY FOR THE ANALYSIS OF TRADITIONAL CHINESE MEDICINE

    Science.gov (United States)

    Huang, Huilian; Liu, Min; Chen, Pei

    2014-01-01

    Traditional Chinese medicine has been widely used for the prevention and treatment of various diseases for thousands of years in China. Ultra-high performance liquid chromatography (UHPLC) is a relatively new technique offering new possibilities. This paper reviews recent developments in UHPLC in the separation and identification, fingerprinting, quantification, and metabolism of traditional Chinese medicine. Recently, the combination of UHPLC with MS has improved the efficiency of the analysis of these materials. PMID:25045170

  1. Toxic Compounds Analysis With High Performance Liquid Chromatography Detected By Electro Chemical Detector (Ecd)

    OpenAIRE

    Hideharu Shintaniq

    2014-01-01

    The principal area of application of high performance liquid chromatography-electrochemical detector (HPLC-ECD) has been in the analysis of naturally-occurring analytes, such as catecholamines, and pharmaceuticals in biological samples, HPLC-ECD has also applied to the analysis of pesticides and other analytes of interest to the toxicologist. In this paper, toxic area is described. In these, ammatoxins, aromatic amine, nitro-compounds, algal toxins, fungal toxins, pesticides, veterinary drug ...

  2. Resolution of the stereoisomers of baclofen by high performance liquid chromatography

    International Nuclear Information System (INIS)

    Weatherby, R.P.; Allan, R.D.; Johnston, G.A.R.

    1984-01-01

    The GABA analogue baclofen [3-(p-chlorophenyl)-4-aminobutanoic acid] has stereospecific actions on the peripheral and central nervous systems. This paper describes the resolution of tritium-labelled baclofen by high performance liquid chromatography on a reverse-phase C18 column using a chiral mobile phase. The method, which may have general application to certain other GABA analogues, affords optically pure (+)- and (-)-baclofen labelled with tritium to high specific activity suitable for ligand binding and other neurochemical studies. (Auth.)

  3. Quantitative analysis of cytokinins in plants by liquid chromatography single-quadrupole mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Novák, Ondřej; Tarkowski, Petr; Tarkowská, Danuše; Doležal, Karel; Lenobel, René; Strnad, Miroslav

    2003-01-01

    Roč. 480, č. 2 (2003), s. 207ů218 ISSN 0003-2670 R&D Projects: GA ČR GA522/01/0275 Grant - others:Volkswagen Stiftung(DE) I/76 865 Institutional research plan: CEZ:AV0Z5038910; CEZ:MSM 153100008 Keywords : Liquid chromatography mass spectrometry * Cytokinins Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.210, year: 2003

  4. Fingerprint analysis of Resina Draconis by ultra-performance liquid chromatography

    OpenAIRE

    Xue, Yudi; Zhu, Lin; Yi, Tao

    2017-01-01

    Background Resina Draconis, a bright red resin derived from Dracaena cochinchinensis, is a traditional medicine used in China. To improve its quality control approach, an ultra-performance liquid chromatography (UPLC) fingerprint method was developed for rapidly evaluating the quality of Resina Draconis. Methods The precision, repeatability and stability of the proposed UPLC method were validated in the study. Twelve batches of Resina Draconis samples from various sources were analyzed by the...

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

    Science.gov (United States)

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

    2015-01-01

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

  6. Simultaneous determination of several phytohormones in natural coconut juice by hollow fiber-based liquid-liquid-liquid microextraction-high performance liquid chromatography.

    Science.gov (United States)

    Wu, Yunli; Hu, Bin

    2009-11-06

    A simple, selective, sensitive and inexpensive method of hollow fiber-based liquid-liquid-liquid microextraction (HF-LLLME) combined with high performance liquid chromatography (HPLC)-ultraviolet (UV) detection was developed for the determination of four acidic phytohormones (salicylic acid (SA), indole-3-acetic acid (IAA), (+/-) abscisic acid (ABA) and (+/-) jasmonic acid (JA)) in natural coconut juice. To the best of our knowledge, this is the first report on the use of liquid phase microextraction (LPME) as a sample pretreatment technique for the simultaneous analysis of several phytohormones. Using phenetole to fill the pores of hollow fiber as the organic phase, 0.1molL(-1) NaOH solution in the lumen of hollow fiber as the acceptor phase and 1molL(-1) HCl as the donor phase, a simultaneous preconcentration of four target phytohormones was realized. The acceptor phase was finally withdrawn into the microsyringe and directly injected into HPLC for the separation and quantification of the target phytohormones. The factors affecting the extraction efficiency of four phytohormones by HF-LLLME were optimized with orthogonal design experiment, and the data was analyzed by Statistical Product and Service Solutions (SPSS) software. Under the optimized conditions, the enrichment factors for SA, IAA, ABA and JA were 243, 215, 52 and 48, with the detection limits (S/N=3) of 4.6, 1.3, 0.9ngmL(-1) and 8.8 microg mL(-1), respectively. The relative standard deviations (RSDs, n=7) were 7.9, 4.9, 6.8% at 50ngmL(-1) level for SA, IAA, ABA and 8.4% at 500 microg mL(-1) for JA, respectively. To evaluate the accuracy of the method, the developed method was applied for the simultaneous analysis of several phytohormones in five natural coconut juice samples, and the recoveries for the spiked samples were in the range of 88.3-119.1%.

  7. Applications of the solvation parameter model in reversed-phase liquid chromatography.

    Science.gov (United States)

    Poole, Colin F; Lenca, Nicole

    2017-02-24

    The solvation parameter model is widely used to provide insight into the retention mechanism in reversed-phase liquid chromatography, for column characterization, and in the development of surrogate chromatographic models for biopartitioning processes. The properties of the separation system are described by five system constants representing all possible intermolecular interactions for neutral molecules. The general model can be extended to include ions and enantiomers by adding new descriptors to encode the specific properties of these compounds. System maps provide a comprehensive overview of the separation system as a function of mobile phase composition and/or temperature for method development. The solvation parameter model has been applied to gradient elution separations but here theory and practice suggest a cautious approach since the interpretation of system and compound properties derived from its use are approximate. A growing application of the solvation parameter model in reversed-phase liquid chromatography is the screening of surrogate chromatographic systems for estimating biopartitioning properties. Throughout the discussion of the above topics success as well as known and likely deficiencies of the solvation parameter model are described with an emphasis on the role of the heterogeneous properties of the interphase region on the interpretation and understanding of the general retention mechanism in reversed-phase liquid chromatography for porous chemically bonded sorbents. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Characterization of the efficiency of microbore liquid chromatography columns by van Deemter and kinetic plot analysis.

    Science.gov (United States)

    Hetzel, Terence; Loeker, Denise; Teutenberg, Thorsten; Schmidt, Torsten C

    2016-10-01

    The efficiency of miniaturized liquid chromatography columns with inner diameters between 200 and 300 μm has been investigated using a dedicated micro-liquid chromatography system. Fully porous, core-shell and monolithic commercially available stationary phases were compared applying van Deemter and kinetic plot analysis. The sub-2 μm fully porous as well as the 2.7 μm core-shell particle packed columns showed superior efficiency and similar values for the minimum reduced plate heights (2.56-2.69) before correction for extra-column contribution compared to normal-bore columns. Moreover, the influence of extra-column contribution was investigated to demonstrate the difference between apparent and intrinsic efficiency by replacing the column by a zero dead volume union to determine the band spreading caused by the system. It was demonstrated that 72% of the intrinsic efficiency could be reached. The results of the kinetic plot analysis indicate the superior performance of the sub-2 μm fully porous particle packed column for ultra-fast liquid chromatography. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Separation of enantiomers of new psychoactive substances by high-performance liquid chromatography.

    Science.gov (United States)

    Kadkhodaei, Kian; Forcher, Lisa; Schmid, Martin G

    2018-03-01

    New psychoactive substances are defined as compounds with consciousness-changing effects and have been developed simultaneously with classical drugs. They arise through structural modifications of illegal substances and are mainly produced to circumvent laws. Availability is simple, since new psychoactive substances can be purchased from the Internet. Among them many chemical drug compound classes are chiral and thus the two resulting enantiomers can differ in their effects. The aim of this study is to develop a suitable chiral high-performance liquid chromatography separation method for a broad spectrum of new psychoactive substances using cellulose tris(3,5-dichlorophenylcarbamate) as a chiral selector. Experiments were performed by high-performance liquid chromatography in normal-phase mode under isocratic conditions using ultraviolet detection. Direct separation was carried out on a high-performance liquid chromatography column (Lux® i-Cellulose-5, 3.5 μm, Phenomenex®), available since 2016. Excellent separation results were obtained for cathinones. After further optimization, even 47 instead of 39 out of 52 cathinones showed baseline separation. For amphetamine derivatives, satisfactory results were not achieved. Further, new psychoactive substances from other compound classes such as benzofuranes, thiophenes, phenidines, phenidates, morpholines, and ketamines were partially resolved, depending on the polarity and degree of substitution. All analytes, which were mainly purchased from the Internet, were proven to be traded as racemates. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Determination of veterinary antibiotic residues in foods of animal origin by liquid chromatography

    Directory of Open Access Journals (Sweden)

    Pedro Enrique La Rosa Zambrano

    2018-05-01

    Full Text Available TITLE: Determination of veterinary antibiotic residues in foods of animal origin by liquid chromatography Introduction: The presence of certain infectious agents makes necessary the use of antibiotics to ensure the welfare of animals destined for human consumption; however, the withdrawal time must be considered and respected since there is the possibility of finding residues above the permitted levels, which could constitute a risk to public health. Objective: Present a collection of information based on how is performed the detection and quantification of antibiotic residues in various products of animal origin using chromatography methods. Method: Review of databases in Elsevier, SciELO, Springer, Hindawi, FAO, EFSA, Senasa and Sanipes, using keywords such as “liquid chromatography”, “mass spectrometry”, “antibiotic residues” and “products of animal origin” in Spanish and English. Results: They were selected 71 references among articles, book chapters, norms and regulations published between 2000 and 2017, which it is emphasized that chromatographic methodologies for antibiotic residues monitoring must be sensitive, reproducible, reliable and identify volumes in mg/kg; likewise, they must follow the requirements of international standards for the maximum residue limits detecction. Conclusions: Liquid chromatography coupled to a mass spectrometer is the most used technique to allow the separation of complex matrices based on the molecular weight of the compound (antibiotic or its fragments; however, It is complex, expensive and requires highly trained personnel.

  11. Characterization of pitches by liquid chromatography using cellulose 3,5-dinitrobenzoate as the packing material

    Energy Technology Data Exchange (ETDEWEB)

    Arai, K.; Judo, R.; Ota, E. [Gunma University, Gunma (Japan). Dept. of Chemistry

    1997-08-01

    Characterization of coal tar, petroleum and PVC pitches by a liquid chromatography using cellulose 3,5-dinitrobenzoate (DNB-cellulose) as the packing material was investigated. Separation mechanism based on charge-transfer interaction between the dinitrobenzoyl group and polyaromatic compounds was expected to be useful for separation of the constituents of the pitches. First, 26 model polyaromatic compounds were tested to examine the characteristic feature of the packing material by liquid chromatography. The compounds were found to be classified roughly into four groups with different retention volume, principally according to the number of condensed rings. The nonplanar structure and aliphatic side chain of the polyaromatic compounds also affected the separation behavior. Both benzene soluble-hexane soluble and benzene soluble-hexane insoluble fractions of the three pitches were separated on DNB-cellulose. It was found that coal tar pitch contains relatively large amounts of some highly condensed polyaromatic compounds with condensed rings of 4 to 5; petroleum pitch has small amounts of such specific highly condensed polyaromatic compounds, while PVC pitch has large amounts of less condensed polyaromatic compounds and there is no significant amount of highly condensed compound in it. Thus DNB-cellulose was useful as the convenient packing material for liquid chromatography to characterize pitches.

  12. Optimization of the combination micro-high-performance liquid-chromatography/mass spectrometry

    International Nuclear Information System (INIS)

    Haider, K.

    1997-03-01

    The coupling of liquid chromatography and mass spectrometry is still growing in significance. In this thesis, a particle beam interface has been investigated for combining ion chromatography with mass spectrometric detection. To introduce the eluent directly (without membrane suppressor) into the spectrometer, only methods with low flow rates like microcolumn chromatography can be used. For the preparation of the columns, reversed-phase and silica-based anion exchange materials were packed into PEEK, steel and fused-silica capillaries with i.d. from 130 to 1000 μm using different methods. The performance of the particle beam interface (modified with a new miniaturized aerosol generator) and the mass spectrometric detection has been studied for a series of inorganic anions as well as aminopolycarboxylic acids and the metal-EDTA complexes. Detection limits between 10 and 100 ng injected could be achieved in the multiple ion detection mode of the mass spectrometer for the investigated solutes. A second type of interface, the direct liquid introduction (DLI) has been used to analyze the priority pollutant phenols. This interface is based on a modified GC-interface into the MS. Separation columns used so far include packed fused-silica capillaries with inner diameter of 75 μm and polystyrene-divinylbenzene (functionalized with tert. butyl groups) as stationary phase. Aspects of instrumentation and effects of chemical ionization in the direct liquid introduction mode are discussed. (author)

  13. Determination of carbofuran on hydrophilic interaction liquid chromatography using TSK gel amide 80 as stationary phase

    International Nuclear Information System (INIS)

    A Kurnia; LW Lim; T Takeuchi

    2016-01-01

    The hydrophilic interaction liquid chromatography (HILIC) coupled to environmental friendly capillary liquid chromatography was employed to investigate retention behavior of carbofuran. Aim of this research is to investigate retention behavior of carbofuran using TSK gel amide 80 as stationary phase. Several condition was conducted to investigate retention behavior of carbofuran such as comparison study of TSK gel amide 80 with other polar column, comparison study retention behavior of carbofuran on various system wavelength, water content effect in HILIC mode, effect of buffer concentration on HILIC mode, and analytical performance. Results showed that TSK gel imidazole was superior compare to other polar stationary phase on determine carbofuran, wavelength 251 and 254 nm was resulting higher absorbance for carbofuran than others, increase of water content on mobile phase was decrease the retention time, also increase buffer salt concentration was decrease the retention time and according to analysis performance that is the accuracy was 101±10,1, the LOD 0.66 ppm while LOQ 2.22 ppm. As conclusions that TSK gel amide 80 was offering good determine on carbofuran even using capillary liquid chromatography with 10 cm length of column. (author)

  14. Simultaneous determination of niacin and pyridoxine at trace levels by using diode array high-performance liquid chromatography and liquid chromatography with quadrupole time-of-flight tandem mass spectrometry.

    Science.gov (United States)

    Sel, Sabriye; Öztürk Er, Elif; Bakırdere, Sezgin

    2017-12-01

    A highly sensitive and simple diode-array high-performance liquid chromatography and liquid chromatography with quadrupole time-of-flight tandem mass spectrometry method was developed for the simultaneous determination of niacin and pyridoxine in pharmaceutical drugs, tap water, and wastewater samples. To determine the in vivo behavior of niacin and pyridoxine, analytes were subjected to simulated gastric conditions. The calibration plots of the diode-array high-performance liquid chromatography and liquid chromatography with quadrupole time-of-flight tandem mass spectrometry method showed good linearity over a wide concentration range with close to 1.0 correlation coefficients for both analytes. The limit of detection/limit of quantitation values for liquid chromatography quadrupole time-of-flight tandem mass spectrometry analysis were 1.98/6.59 and 1.3/4.4 μg/L for niacin and pyridoxine, respectively, while limit of detection/limit of quantitation values for niacin and pyridoxine in high-performance liquid chromatography analysis were 3.7/12.3 and 5.7/18.9 μg/L, respectively. Recovery studies were also performed to show the applicability of the developed methods, and percentage recovery values were found to be 90-105% in tap water and 94-97% in wastewater for both analytes. The method was also successfully applied for the qualitative and quantitative determination of niacin and pyridoxine in drug samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Gas chromatography-mass spectrometry and high-performance liquid chromatographic analyses of thermal degradation products of common plastics

    OpenAIRE

    Pacakova, V.; Leclercq, P.A.

    1991-01-01

    The thermo-oxidation of five commonly used materials, namely low-density polyethylene, retarded polyethylene, paper with a polyethylene foil, a milk package and filled polypropylene, was studied. Capillary gas chromatography and gas chromatography-mass spectrometry were used to analyze the volatile degradation products, while high-performance liquid chromatography was employed to measure polycyclic aromatic hydrocarbons. The results are discussed from the point of view of toxicity of the prod...

  16. Multielement determination of rare earth elements in rock sample by liquid chromatography / inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Hamanaka, Tadashi; Itoh, Akihide; Itoh, Shinya; Sawatari, Hideyuki; Haraguchi, Hiroki.

    1995-01-01

    Rare earth elements in geological standard rock sample JG-1 (granodiolite)issued from the Geological Survey of Japan have been determined by a combined system of liquid chromatography and inductively coupled plasma mass spectrometry. (author)

  17. EXTRACTION AND QUANTITATIVE ANALYSIS OF ELEMENTAL SULFUR FROM SULFIDE MINERAL SURFACES BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY. (R826189)

    Science.gov (United States)

    A simple method for the quantitative determination of elemental sulfur on oxidized sulfide minerals is described. Extraction of elemental sulfur in perchloroethylene and subsequent analysis with high-performance liquid chromatography were used to ascertain the total elemental ...

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

    NARCIS (Netherlands)

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

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

  19. Determination of ten carbamate pesticides in aquatic and sediment samples by liquid chromatography-ionspray and thermospray mass spectrometry.

    NARCIS (Netherlands)

    Honing, M.; Riu, J.; Barceló, D.; van Baar, B.L.M.; Brinkman, U.A.T.

    1996-01-01

    Ten carbamate pesticides which exhibit large differences in polarity were determined simultaneously in various environmental samples, using both column liquid chromatography (LC)-thermospray (TSP) mass spectrometry (MS) and LC-ionspray (ISP) MS. For sample clean-up, column chromatography with three

  20. Preparation and Characterization of a Polymeric Monolithic Column for Use in High-Performance Liquid Chromatography (HPLC)

    Science.gov (United States)

    Bindis, Michael P.; Bretz, Stacey Lowery; Danielson, Neil D.

    2011-01-01

    The high-performance liquid chromatography (HPLC) experiment, most often done in the undergraduate analytical instrumentation laboratory course, generally illustrates reversed-phase chromatography using a commercial C[subscript]18 silica column. To avoid the expense of periodic column replacement and introduce a choice of columns with different…

  1. tRNA separation by high-performance liquid chromatography using an aggregate of ODS-Hypersil and trioctylmethylammonium chloride

    NARCIS (Netherlands)

    Bischoff, Rainer; Graeser, E.; Mclaughlin, L.W.

    1983-01-01

    High-performance liquid chromatography on a reversed-phase support treated with a tetraalkylammonium salt was used to separate tRNAs from baker's yeast. While resolution by this column appears to result from both anion-exchange and reversed-phase chromatography, it is the hydrophobic interactions

  2. Quantitative analysis of pharmaceuticals in biological fluids using high-performance liquid chromatography coupled to mass spectrometry: a review.

    Science.gov (United States)

    Plumb, R S; Dear, G J; Mallett, D N; Higton, D M; Pleasance, S; Biddlecombe, R A

    2001-01-01

    1. The development of bio-analysis of drug molecules over the last 10 years is reviewed, focusing on advances in sample preparation, liquid chromatography and detection. 2. Developments have led to improvements in detection sensitivity, enhancements in specificity and increased capacity. 3. Emerging technologies such as monolithic column chromatography and miniaturized chip-based systems are discussed.

  3. Investigation of forced and total degradation products of amlodipine besylate by liquid chromatography and liquid chromatography-mass spectrometry

    Directory of Open Access Journals (Sweden)

    Stoiljković Zora Ž.

    2014-01-01

    Full Text Available An isocratic, reversed-phase liquid chromatographic method was applied for the investigation of the degradation products of amlodipine besylate under the stressed conditions in solution. Amlodipine besylate stock solutions were subjected to acid and alkali hydrolysis, chemical oxidation and photodegradation as well as to the electrochemical degradation by cyclic voltammetry in 0.05 mol/L NaHCO3 on gold electrode. The total degradation of amlodipine besylate was achieved in 5 mol/L NaOH at 80°C for 6 h and the compound with molecular formula C15H16NOCl was identified as a main degradation product. Under acidic (5 mol/L HCl at 80°C for 6 h stress conditions 75.2% of amlodipine besylate degradation was recorded. Oxidative degradation in the solution of 3% H2O2-methanol 80:20 at 80°C for 6 h showed that amlodipine besylate degraded to 80.1%. After 14 days of expose in photostability chamber amlodipine besylate solution showed degradation of 32.2%. In electrochemical degradation after 9 hours of cyclization the beginning of amlodipine oxidation was shifted for 200 mV to more negative potentials, with the degradation of 66.5%. Mass spectrometry analysis confirmed the presence of dehydro amlodipine derivate with molecular formula C20H23N2O5Cl in oxidative and acidic conditions while in electrochemical degradation was detected in traces. [Projekat Ministarsva nauke Republike Srbije, br. 172013

  4. Quantitative analysis of phylloquinone (vitamin K1) in soy bean oils by high-performance liquid chromatography.

    Science.gov (United States)

    Zonta, F; Stancher, B

    1985-07-19

    A high-performance liquid chromatographic method for determining phylloquinone (vitamin K1) in soy bean oils is described. Resolution of vitamin K1 from interfering peaks of the matrix was obtained after enzymatic digestion, extraction and liquid-solid chromatography on alumina. An isocratic reversed-phase chromatography with UV detection was used in the final stage. The quantitation was carried out by the standard addition method, and the recovery of the whole procedure was 88.2%.

  5. Stationary and through-flow radiochemical detectors in cooperation with high performance liquid chromatography: Application in biochemistry

    International Nuclear Information System (INIS)

    Kehr, J.

    1986-01-01

    A review article is presented containing some original experimental data and discussing the usability of radiochemical detection of labelled compounds using high performance liquid chromatography. The stationary and through-flow types of detection are compared with respect to efficiency, chromatographic zone resolution, usability in biochemical research, and also to the current trends of development of liquid chromatography. (author). 3 figs., 1 tab., 19 refs

  6. Deformation and degradation of polymers in ultra-high-pressure liquid chromatography.

    Science.gov (United States)

    Uliyanchenko, Elena; van der Wal, Sjoerd; Schoenmakers, Peter J

    2011-09-28

    Ultra-high-pressure liquid chromatography (UHPLC) using columns packed with sub-2 μm particles has great potential for separations of many types of complex samples, including polymers. However, the application of UHPLC for the analysis of polymers meets some fundamental obstacles. Small particles and narrow bore tubing in combination with high pressures generate significant shear and extensional forces in UHPLC systems, which may affect polymer chains. At high stress conditions flexible macromolecules may become extended and eventually the chemical bonds in the molecules can break. Deformation and degradation of macromolecules will affect the peak retention and the peak shape in the chromatogram, which may cause errors in the obtained results (e.g. the calculated molecular-weight distributions). In the present work we explored the limitations of UHPLC for the analysis of polymers. Degradation and deformation of macromolecules were studied by collecting and re-injecting polymer peaks and by off-line two-dimensional liquid chromatography. Polystyrene standards with molecular weight of 4 MDa and larger were found to degrade at UHPLC conditions. However, for most polymers degradation could be avoided by using low linear velocities. No degradation of 3-MDa PS (and smaller) was observed at linear velocities up to 7 mm/s. The column frits were implicated as the main sources of polymer degradation. The extent of degradation was found to depend on the type of the column and on the column history. At high flow rates degradation was observed without a column being installed. We demonstrated that polymer deformation preceded degradation. Stretched polymers eluted from the column in slalom chromatography mode (elution order opposite to that in SEC or HDC). Under certain conditions we observed co-elution of large and small PS molecules though a convolution of slalom chromatography and hydrodynamic chromatography. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Determination of parabens in serum by liquid chromatography-tandem mass spectrometry: Correlation with lipstick use.

    Science.gov (United States)

    Tahan, Gabriella Padovani; Santos, Nayara de Kássia Souza; Albuquerque, Ana Carolina; Martins, Isarita

    2016-08-01

    Parabens are the most widely used preservative and are considered to be relatively safe compounds. However, studies have demonstrated that they may have estrogenic activity, and there is ongoing debate regarding the safety and potential cancer risk of using products containing these compounds. In the present work, liquid chromatography-tandem mass spectrometry was applied to determine methylparaben and propylparaben concentrations in serum, and the results were correlated with lipstick application. Samples were analyzed using liquid-liquid extraction, followed by liquid chromatography-tandem mass spectrometry. The validation results demonstrated the linearity of the method over a range of 1-20 ng/mL, in addition to the method's precision and accuracy. A statistically significant difference was demonstrated between serum parabens in women who used lipstick containing these substances compared with those not using this cosmetic (p = 0.0005 and 0.0016, respectively), and a strong association was observed between serum parabens and lipstick use (Spearman correlation = 0.7202). Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Quantitative analysis of benzodiazepines in vitreous humor by high-performance liquid chromatography

    Science.gov (United States)

    Bazmi, Elham; Behnoush, Behnam; Akhgari, Maryam; Bahmanabadi, Leila

    2016-01-01

    Objective: Benzodiazepines are frequently screened drugs in emergency toxicology, drugs of abuse testing, and in forensic cases. As the variations of benzodiazepines concentrations in biological samples during bleeding, postmortem changes, and redistribution could be biasing forensic medicine examinations, hence selecting a suitable sample and a validated accurate method is essential for the quantitative analysis of these main drug categories. The aim of this study was to develop a valid method for the determination of four benzodiazepines (flurazepam, lorazepam, alprazolam, and diazepam) in vitreous humor using liquid–liquid extraction and high-performance liquid chromatography. Methods: Sample preparation was carried out using liquid–liquid extraction with n-hexane: ethyl acetate and subsequent detection by high-performance liquid chromatography method coupled to diode array detector. This method was applied to quantify benzodiazepines in 21 authentic vitreous humor samples. Linear curve for each drug was obtained within the range of 30–3000 ng/mL with coefficient of correlation higher than 0.99. Results: The limit of detection and quantitation were 30 and 100 ng/mL respectively for four drugs. The method showed an appropriate intra- and inter-day precision (coefficient of variation forensic toxicology laboratory. PMID:27635251

  9. Analysis of aromatic amines in water samples by liquid-liquid-liquid microextraction with hollow fibers and high-performance liquid chromatography.

    Science.gov (United States)

    Zhao, Limian; Zhu, Lingyan; Lee, Hian Kee

    2002-07-19

    Liquid-liquid-liquid microextraction (LLLME) with hollow fibers in high-performance liquid chromatography (HPLC) has been applied as a rapid and sensitive quantitative method for the detection of four aromatic amines (3-nitroaniline, 4-chloroaniline, 4-bromoaniline and 3,4-dichloroaniline) in environmental water samples. The preconcentration procedure was induced by the pH difference inside and outside the hollow fiber. The target compounds were extracted from 4-ml aqueous sample (donor solution, pH approximately 13) through a microfilm of organic solvent (di-n-hexyl ether), immobilized in the pores of a hollow fiber (1.5 cm length x 0.6 mm I.D.), and finally into 4 microl of acid acceptor solution inside the fiber. After a prescribed period of time, the acceptor solution inside the fiber was withdrawn into the microsyringe and directly injected into the HPLC system for analysis. Factors relevant to the extraction procedure were studied. Up to 500-fold enrichment of analytes could be obtained under the optimized conditions (donor solution: 0.1 M sodium hydroxide solution with 20% sodium chloride and 2% acetone; organic phase: di-n-hexyl ether; acceptor solution: 0.5 M hydrochloric acid and 500 mM 18-crown-6 ether; extraction time of 30 min; stirring at 1,000 rev./min). The procedure also served as a sample clean-up step. The influence of humic acid on the extraction efficiency was also investigated, and more than 85% relative recoveries of the analytes at two different concentrations (20 and 100 microg/l) were achieved at various concentration of humic acid. This technique is a low cost, simple and fast approach to the analysis of polar compounds in aqueous samples.

  10. Incorporation of ionic liquid into porous polymer monoliths to enhance the separation of small molecules in reversed-phase high-performance liquid chromatography.

    Science.gov (United States)

    Wang, Jiafei; Bai, Ligai; Wei, Zhen; Qin, Junxiao; Ma, Yamin; Liu, Haiyan

    2015-06-01

    An ionic liquid was incorporated into the porous polymer monoliths to afford stationary phases with enhanced chromatographic performance for small molecules in reversed-phase high-performance liquid chromatography. The effect of the ionic liquid in the polymerization mixture on the performance of the monoliths was studied in detail. While monoliths without ionic liquid exhibited poor resolution and low efficiency, the addition of ionic liquid to the polymerization mixture provides highly increased resolution and high efficiency. The chromatographic performances of the monoliths were demonstrated by the separations of various small molecules including aromatic hydrocarbons, isomers, and homologues using a binary polar mobile phase. The present column efficiency reached 27 000 plates/m, which showed that the ionic liquid monoliths are alternative stationary phases in the separation of small molecules by high-performance liquid chromatography. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. High-performance liquid chromatography analysis methods developed for quantifying enzymatic esterification of flavonoids in ionic liquids.

    Science.gov (United States)

    Lue, Bena-Marie; Guo, Zheng; Xu, Xuebing

    2008-07-11

    Methods using reversed-phase high-performance liquid chromatography (RP-HPLC) with ELSD were investigated to quantify enzymatic reactions of flavonoids with fatty acids in the presence of diverse room temperature ionic liquids (RTILs). A buffered salt (preferably triethylamine-acetate) was found essential for separation of flavonoids from strongly polar RTILs, whereby RTILs were generally visible as two major peaks identified based on an ion-pairing/exchanging hypothesis. C8 and C12 stationary phases were optimal while mobile phase pH (3-7) had only a minor influence on separation. The method developed was successfully applied for primary screening of RTILs (>20), with in depth evaluation of substrates in 10 RTILs, for their evaluation as reaction media.

  12. Screening anti-tumor compounds from Ligusticum wallichii using cell membrane chromatography combined with high-performance liquid chromatography and mass spectrometry.

    Science.gov (United States)

    Zhang, Tao; Ding, Yuanyuan; An, Hongli; Feng, Liuxin; Wang, Sicen

    2015-07-14

    Tyrosine 367 Cysteine-fibroblast growth factor receptor 4 cell membrane chromatography combined with high-performance liquid chromatography and mass spectrometry was developed. Tyrosine 367 Cysteine-HEK293 cells were used as cell membrane stationary phase. Specificity and reproducibility of the cell membrane chromatography was evaluated using 1-tert-butyl-3-{2-[4-(diethylamino)butylamino]-6-(3,5-dimethoxyphenyl)pyrido[2,3-d]pyrimidin-7-yl}urea, Nimodipine and dexamethasone acetate. Then, anti-tumor components acting on Tyrosine 367 Cysteine-fibroblast growth factor receptor 4 were screened and identified from extracts of Ligusticum wallichii. Components from the extract were retained on the cell membrane chromatographic column. The retained fraction was directly eluted into high-performance liquid chromatography with mass spectrometry system for separation and identification. Finally, Levistolide A was identified as an active component from Ligusticum wallichii extracts. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide-formazan colorimetric assay revealed that Levistolide A inhibits proliferation of overexpressing the mutated receptor cells with dose-dependent manner. Phosphorylation of fibroblast growth factor receptor 4 was also decrease under Levistolide A treatment. Flex dock simulation verified that Levistolide A could bind with the tyrosine kinase domain of fibroblast growth factor receptor 4. Therefore, Levistolide A screened by the cell membrane chromatography combined with high-performance liquid chromatography and mass spectrometry can arrest cell growth. In conclusion, the two-dimensional high-performance liquid chromatography method can screen and identify potential anti-tumor ingredients which specifically act on the tyrosine kinase domain of the mutated fibroblast growth factor receptor 4. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  13. Determination of Alternaria mycotoxins in wine and juice using ionic liquid modified countercurrent chromatography as a pretreatment method followed by high-performance liquid chromatography.

    Science.gov (United States)

    Fan, Chen; Cao, Xueli; Liu, Man; Wang, Wei

    2016-03-04

    Alternariol (AOH), alternariol monomethyl ether (AME), and tenuazonic acid (TeA) are some of the main Alternaria mycotoxins that can be found as contaminants in food materials. The objective of this study was to develop a pretreatment method with countercurrent chromatography (CCC) for enrichment and cleanup of trace Alternaria mycotoxins in food samples prior to high-performance liquid chromatography (HPLC) analysis. An Analytical CCC instrument with a column volume 22.5mL was used, and a two-phase solvent system composed of ethyl acetate and water modified with 6% [HOOMIM][Cl] in mass to volume ratio was selected. Under the optimized CCC operation conditions, trace amounts of AOH, AME, and TeA in large volume of liquid sample were efficiently extracted and enriched in the stationary phase, and then eluted out just by reversing the stationary phase as mobile phase in the opposite flowing direction tail-to-head. The enrichment and elution strategies are unique and can be fulfilled online with high enrichment factors (87-114) and high recoveries (81.14-110.94%). The method has been successively applied to the determination of Alternaria mycotoxins in real apple juice and wine samples with the limits of detection (LOD) in the range of 0.03-0.14μgL(-1). Totally 12 wine samples and 15 apple juice samples from the local market were analyzed. The detection rate of AOH and AME in both kinds of the samples were more than 50%, while TeA was found in relatively high level of 1.75-49.61μgL(-1) in some of the apple juice samples. The proposed method is simple, rapid, and sensitive and could also be used for the analysis and monitoring of Alternaria mycotoxin in other food samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Home-made online hyphenation of pressurized liquid extraction, turbulent flow chromatography, and high performance liquid chromatography, Cistanche deserticola as a case study.

    Science.gov (United States)

    Song, Qingqing; Li, Jun; Liu, Xiao; Zhang, Yuan; Guo, Liping; Jiang, Yong; Song, Yuelin; Tu, Pengfei

    2016-03-18

    Incompatibility between the conventional pressurized liquid extraction (PLE) devices and high performance liquid chromatography (HPLC) extensively hinders direct and green chemical analysis of herbal materials. Herein, a facile PLE module was configured, and then it was online hyphenated with HPLC via a turbulent flow chromatography (TFC) column. Regarding PLE module, a long PEEK tube (0.13 × 1000 mm) was employed to generate desired pressure (approximately 13.0 MPa) when warm acidic water (70 °C) was delivered as extraction solvent at a high flow rate (2.5 mL/min), and a hollow guard column (3.0 × 4.0 mm) was implemented to hold crude materials. Effluent was collected from the outlet of PEEK tube, concentrated, and subjected onto HPLC coupled with hybrid ion trap-time of flight mass spectrometer to assess the extraction efficiency and also to profile the chemical composition of Cistanche deserticola (CD) that is honored as "Ginseng of the desert". Afterwards, a TFC column was introduced to accomplish online transmission of low molecule weight components from PLE module to HPLC coupled with diode array detection, and two electronic 6-port/2-channel valves were in charge of alternating the whole system between extraction (0-3.0 min) and elution (3.0-35.0 min) phases. Quantitative method was developed and validated for simultaneous determination of eight primary phenylethanoid glycosides in CD using online PLE-TFC-HPLC. All findings demonstrated that the home-made platform is advantageous at direct chemical analysis, as well as time-, solvent-, and material-savings, suggesting a robust tool for chemical fingerprinting of herbs. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Comprehensive two-dimensional liquid chromatography with on-line Fourier-transform-infrared-spectroscopy detection for the characterization of copolymers

    NARCIS (Netherlands)

    Kok, S.J.; Hankemeier, T.; Schoenmakers, P.J.

    2005-01-01

    The on-line coupling of comprehensive two-dimensional liquid chromatography (liquid chromatography × size-exclusion chromatography, LC × SEC) and infrared (IR) spectroscopy has been realized by means of an IR flow cell. The system has been assessed by the functional-group analysis of a series of

  16. Determination of ppq-levels of alkylmethoxypyrazines in wine by stirbar sorptive extraction combined with multidimensional gas chromatography-mass spectrometry.

    Science.gov (United States)

    Wen, Yan; Ontañon, Ignacio; Ferreira, Vicente; Lopez, Ricardo

    2018-07-30

    Alkylmethoxypyrazines are powerful odorants in many food products. A new method for analysing 3-isopropyl-2-methoxypyrazine, 3-s-butyl-2-methoxypyrazine and 3-isobutyl-2-methoxypyrazine has been developed and applied to wine. The analytes were extracted from 5 mL of wine using stirbar sorptive extraction followed by thermal desorption and multidimensional gas chromatography-mass spectrometry analysis in a single oven. The extraction conditions were optimized in order to obtain a high recovery of the 3-alkyl-2-methoxypyrazines (MP). The detection limits of the method in all cases were under 0.08 ng/L, well below the olfactory thresholds of these compounds in wine. The reproducibility of the method was adequate (below 10%), the linearity satisfactory and the recoveries in all cases close to 100%. The method has been applied to the analysis of 111 Spanish and French wine samples. The levels found suggest that MP have a low direct impact on the aroma properties of wines from the regions around the Pyrenean massif. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

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

    Science.gov (United States)

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

    2015-09-01

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

  18. Miniaturized protein separation using a liquid chromatography column on a flexible substrate

    International Nuclear Information System (INIS)

    Yang Yongmo; Chae, Junseok

    2008-01-01

    We report a prototype protein separator that successfully miniaturizes existing technology for potential use in biocompatible health monitoring implants. The prototype is a liquid chromatography (LC) column (LC mini-column) fabricated on an inexpensive, flexible, biocompatible polydimethylsiloxane (PDMS) enclosure. The LC mini-column separates a mixture of proteins using size exclusion chromatography (SEC) with polydivinylbenzene beads (5–20 µm in diameter with 10 nm pore size). The LC mini-column is smaller than any commercially available LC column by a factor of ∼11 000 and successfully separates denatured and native protein mixtures at ∼71 psi of the applied fluidic pressure. Separated proteins are analyzed using NuPAGE-gel electrophoresis, high-performance liquid chromatography (HPLC) and an automated electrophoresis system. Quantitative HPLC results demonstrate successful separation based on intensity change: within 12 min, the intensity between large and small protein peaks changed by a factor of ∼20. In further evaluation using the automated electrophoresis system, the plate height of the LC mini-column is between 36 µm and 100 µm. The prototype LC mini-column shows the potential for real-time health monitoring in applications that require inexpensive, flexible implant technology that can function effectively under non-laboratory conditions

  19. Osteoblast cell membrane chromatography coupled with liquid chromatography and time-of-flight mass spectrometry for screening specific active components from traditional Chinese medicines.

    Science.gov (United States)

    Wang, Nani; Zhang, Qiaoyan; Xin, Hailiang; Shou, Dan; Qin, Luping

    2017-11-01

    A method using osteoblast membrane chromatography coupled with liquid chromatography and time-of-flight mass spectrometry was developed to recognize and identify the specific active components from traditional Chinese medicines. Primary rat osteoblasts were used for the preparation of the stationary phase in the cell chromatography method. Retention components from the cell chromatography were collected and analyzed by liquid chromatography with time-of-flight mass spectrometry. This method was applied in screening active components from extracts of four traditional Chinese medicines. In total, 24 potentially active components with different structures were retained by osteoblast cell chromatography. There were five phenolic glucosides and one triterpenoid saponin from Curculigo orchioides Gaertn, two organic acids and ten flavonoids from Epimedium sagittatum Maxim, one phthalide compound and one organic acid from Angelica sinensis Diels, and two flavonoids and two saponins from Anemarrhena asphodeloides Bunge. Among those, four components (icariin, curculigoside, ferulaic acid, and timosaponin BII) were used for in vitro pharmacodynamics validation. They significantly increased the osteoblast proliferation, alkaline phosphatase activity, levels of bone gla protein and collagen type 1, and promoted mineralized nodule formation. The developed method was an effective screening method for finding active components from complex medicines that act on bone diseases. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    Science.gov (United States)

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

    2014-11-01

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

  1. Determination of the trace TBP in industrial feed liquid by gas chromatography

    International Nuclear Information System (INIS)

    Gao Yuehua; Jiang Junqing; Mu Ling; Yang Songtao

    2012-01-01

    The determination of the trace TBP in kerosene of the industrial feed liquid by gas chromatography is studied in the paper. It first takes the purification treatment for the kerosene containing trace TBP. The plutonium is removed by 0.2 mol/L ferrous sulfamate-1 mol/L nitric acid using the back-extraction. The uranium and the nitric acid in the organic phase are removed by the deionized water. The impurity which affect the measurement of the TBP and is harmful to the gas chromatograph are eliminated. Then the content of the TBP of the organic phase can be determined by gas chromatography. Results show that the measuring range of the content of the TBP is 0.02% ∼ 2%. The precision of the method is better than 5% and the recovery is between 95%∼106%. (authors)

  2. A method for fast determination of psoralens in oral solutions of phytomedicines using liquid chromatography.

    Science.gov (United States)

    Pires, Adriana Elias; Honda, Neli Kiko; Cardoso, Cláudia Andréa Lima

    2004-10-29

    A method for sample preparation and analysis by high performance liquid chromatography with UV detection (HPLC-UV) has been developed for routine analysis of psoralen and bergapten, photosensitizing compounds, in oral solutions of phytomedicines employed in Brazil for some illnesses. The linearity, accuracy, the inter- and intra-day precision of the procedure were evaluated. Calibration curves for psoralen and bergapten were linear in the range of 1.0-600.0 microg ml(-1) and 1.0-400.0 microg ml(-1) respectively. The recoveries of the psoralens in the oral solutions analysed were 94.43-99.97%. The percentage coefficient of variation (CV) of the quantitative analysis of the psoralens in the products analysis was within 5%. In inter-equipment study was employed gas chromatography-flame ionization (CG-FID) detection.

  3. Liquid Chromatography-Tandem Mass Spectrometry: An Emerging Technology in the Toxicology Laboratory.

    Science.gov (United States)

    Zhang, Yan Victoria; Wei, Bin; Zhu, Yu; Zhang, Yanhua; Bluth, Martin H

    2016-12-01

    In the last decade, liquid chromatography-tandem mass spectrometry (LC-MS/MS) has seen enormous growth in routine toxicology laboratories. LC-MS/MS offers significant advantages over other traditional testing, such as immunoassay and gas chromatography-mass spectrometry methodologies. Major strengths of LC-MS/MS include improvement in specificity, flexibility, and sample throughput when compared with other technologies. Here, the basic principles of LC-MS/MS technology are reviewed, followed by advantages and disadvantages of this technology compared with other traditional techniques. In addition, toxicology applications of LC-MS/MS for simultaneous detection of large panels of analytes are presented. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Greening Reversed-Phase Liquid Chromatography Methods Using Alternative Solvents for Pharmaceutical Analysis

    Directory of Open Access Journals (Sweden)

    Moussa Yabré

    2018-05-01

    Full Text Available The greening of analytical methods has gained increasing interest in the field of pharmaceutical analysis to reduce environmental impacts and improve the health safety of analysts. Reversed-phase high-performance liquid chromatography (RP-HPLC is the most widely used analytical technique involved in pharmaceutical drug development and manufacturing, such as the quality control of bulk drugs and pharmaceutical formulations, as well as the analysis of drugs in biological samples. However, RP-HPLC methods commonly use large amounts of organic solvents and generate high quantities of waste to be disposed, leading to some issues in terms of ecological impact and operator safety. In this context, greening HPLC methods is becoming highly desirable. One strategy to reduce the impact of hazardous solvents is to replace classically used organic solvents (i.e., acetonitrile and methanol with greener ones. So far, ethanol has been the most often used alternative organic solvent. Others strategies have followed, such as the use of totally aqueous mobile phases, micellar liquid chromatography, and ionic liquids. These approaches have been well developed, as they do not require equipment investments and are rather economical. This review describes and critically discusses the recent advances in greening RP-HPLC methods dedicated to pharmaceutical analysis based on the use of alternative solvents.

  5. Assessing the detectability of antioxidants in two-dimensional high-performance liquid chromatography.

    Science.gov (United States)

    Bassanese, Danielle N; Conlan, Xavier A; Barnett, Neil W; Stevenson, Paul G

    2015-05-01

    This paper explores the analytical figures of merit of two-dimensional high-performance liquid chromatography for the separation of antioxidant standards. The cumulative two-dimensional high-performance liquid chromatography peak area was calculated for 11 antioxidants by two different methods--the areas reported by the control software and by fitting the data with a Gaussian model; these methods were evaluated for precision and sensitivity. Both methods demonstrated excellent precision in regards to retention time in the second dimension (%RSD below 1.16%) and cumulative second dimension peak area (%RSD below 3.73% from the instrument software and 5.87% for the Gaussian method). Combining areas reported by the high-performance liquid chromatographic control software displayed superior limits of detection, in the order of 1 × 10(-6) M, almost an order of magnitude lower than the Gaussian method for some analytes. The introduction of the countergradient eliminated the strong solvent mismatch between dimensions, leading to a much improved peak shape and better detection limits for quantification. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Protein Stable Isotope Fingerprinting (P-SIF): Multidimensional Protein Chromatography Coupled to Stable Isotope-Ratio Mass Spectrometry

    Science.gov (United States)

    Pearson, A.; Bovee, R. J.; Mohr, W.; Tang, T.

    2012-12-01

    As metagenomics increases our insight into microbial community diversity and metabolic potential, new approaches are required to determine the biogeochemical expression of this potential within ecosystems. Because stable isotopic analysis of the major bioactive elements (C, N) has been used historically to map flows of substrates and energy among macroscopic food webs, similar principles may apply to microbes. To address this challenge, we have developed a new analytical approach called Protein Stable Isotope Fingerprinting (P-SIF). P-SIF generates natural stable isotopic fingerprints of microbial individual or community proteomes. The main advantage of P-SIF is the potential to bridge the gap between diversity and function, thereby providing a window into the "black box" of environmental microbiology and helping to decipher the roles of uncultivated species. Our method implements a three-way, orthogonal scheme to separate mixtures of whole proteins into subfractions dominated by single or closely-related proteins. Protein extracts first are isoelectrically focused in a gel-free technique that yields 12 fractions separated over a gradient of pH 3-10. Each fraction then is separated by size-exclusion chromatography into 20 pools, ranging from >100kD to ~10kD. Finally, each of these pools is subjected to HPLC and collected in 40 time-slices based on protein hydrophobicity. Theoretical calculation reveals that the true chromatographic resolution of the total scheme is 5000, somewhat less than the 9600 resulting fractions. High-yielding fractions are subjected to δ13C analysis by spooling-wire microcombustion irMS (SWiM-irMS) optimized for samples containing 1-5 nmol carbon. Here we will present the method, results for a variety of pure cultures, and preliminary data for a sample of mixed environmental proteins. The data show the promise of this method for unraveling the metabolic complexity hidden within microbial communities.

  7. Analysis of recombinant Schistosoma mansoni antigen rSmp28 by on-line liquid chromatography-mass spectrometry combined with sodium dodecyl sulfate polyacrylamide gel electrophoresis

    NARCIS (Netherlands)

    Klarskov, K.; Roecklin, D.; Bouchon, B.; Sabatie, J.; Van Dorsselaer, A.; Bischoff, Rainer

    1994-01-01

    A recombinant Schistosoma mansoni antigen produced in Saccharomyces cerevisiae and purified by glutathione-Sepharose affinity chromatography was analyzed by tryptic peptide mapping using on-line reversed-phase high-performance liquid chromatography pneumatically assisted electrospray mass

  8. Simultaneous Determination of Eight Bioactive Compounds in Dianthus superbus by High-performance Liquid Chromatography.

    Science.gov (United States)

    Yun, Bo-Ra; Yang, Hye Jin; Weon, Jin Bae; Lee, Jiwoo; Eom, Min Rye; Ma, Choong Je

    2016-05-01

    Dianthus superbus, one of traditional herbal medicine, is widely used to treat urethritis, carbuncles and carcinoma. A simultaneous determination method was established for controlling the quality of D. superbus using the eight compounds, (E)-methyl-4-hydroxy-4-(8a-methyl-3-oxodecahydronaphthalen-4a-yl) (1), diosmetin-7-O(2'',6''-di-O-α-L-rhamnopyranosyl)-β-D-glucopyranoside (2), vanillic acid (3), 4-hydroxyphenyl acetic acid (4), 4-methoxyphenyl acetic acid (5), (E)-4-methoxycinnamic acid (6), 3-methoxy-4-hydroxyphenylethanol (7), and methyl hydroferulate (8) isolated from D. superbus. This analysis method was developed using high performance liquid chromatography coupled with diode array detector with a Shishedo C18 column at a column temperature of 3°C. The mobile phase was composed of 0.1% trifluoroacetic acid in water and acetonitrile. The flow rate was 1 ml/min and detection wavelength was set at 205 nm and 280 nm. Validation was performed in order to demonstrate selectivity, accuracy and precision of the method. The calibration curves showed good linearity (R (2) > 0.99). The limits of detection and limits of quantification were within the ranges 0.0159-0.6205 μg/ml and 0.3210-1.8802 μg/ml, respectively. Moreover, the relative standard deviations of intra- and inter-day precision were both Dianthus superbus was established by high performance liquid chromatography-diode array detectorDeveloped analysis method is validated with linearity, precious and accuracyThe newly established method was successfully evaluated contents of eight compounds in 12 D. superbus samples (D.1.D.12) from various regions and compared. Abbreviations used: HPLC: High performance liquid chromatography, LOD: Limits of detection, LOQ: Limits of quantification, RSD: Relative standard deviation.

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

    Science.gov (United States)

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

    2016-10-07

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

  10. Integration of electrochemistry with ultra-performance liquid chromatography/mass spectrometry.

    Science.gov (United States)

    Cai, Yi; Zheng, Qiuling; Liu, Yong; Helmy, Roy; Loo, Joseph A; Chen, Hao

    2015-01-01

    This study presents the development of ultra-performance liquid chromatography (UPLC) mass spectrometry (MS) combined with electrochemistry (EC) for the first time and its application for the structural analysis of proteins/peptides that contain disulfide bonds. In our approach, a protein/peptide mixture sample undergoes a fast UPLC separation and subsequent electrochemical reduction in an electrochemical flow cell followed by online MS and tandem mass spectrometry (MS/MS) analyses. The electrochemical cell is coupled to the mass spectrometer using our recently developed desorption electrospray ionization (DESI) interface. Using this UPLC/EC/DESI-MS method, peptides that contain disulfide bonds can be differentiated from those without disulfide bonds, as the former are electroactive and reducible. MS/MS analysis of the disulfide-reduced peptide ions provides increased information on the sequence and disulfide-linkage pattern. In a reactive DESI- MS detection experiment in which a supercharging reagent was used to dope the DESI spray solvent, increased charging was obtained for the UPLC-separated proteins. Strikingly, upon online electrolytic reduction, supercharged proteins (e.g., α-lactalbumin) showed even higher charging, which will be useful in top- down protein structure MS analysis as increased charges are known to promote protein ion dissociation. Also, the separation speed and sensitivity are enhanced by approximately 1(~)2 orders of magnitude by using UPLC for the liquid chromatography (LC)/EC/MS platform, in comparison to the previously used high- performance liquid chromatography (HPLC). This UPLC/EC/DESI-MS method combines the power of fast UPLC separation, fast electrochemical conversion, and online MS structural analysis for a potentially valuable tool for proteomics research and bioanalysis.

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

    Science.gov (United States)

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

    2016-04-01

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

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

    Science.gov (United States)

    Çabuk, Hasan; Köktürk, Mustafa

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Hasan Çabuk

    2013-01-01

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

  14. Determination of alpha-Tocopherol (vitamin E) in irradiated garlic by high performance liquid chromatography (HPLC)

    International Nuclear Information System (INIS)

    Rios, Magda Dias Goncalves; Penteado, Marilene de Vuono Camargo

    2003-01-01

    The effects of 60 Co ionizing radiations in doses of 0, 75, 100, 150, 200 and 250Gy on garlic, upon the α-tocopherol concentration were studied. The α-tocopherol contents were established by high performance liquid chromatography (HPLC), after direct hexane extraction from the garlic samples. The α-tocopherol was determined through normal phase column, and mobile phase was composed by hexane: iso-propyl alcohol (99:01 v/v), with 2mL/min flow rate and fluorescence detector. It is statistically shown that an irradiation dose of up to 150 Gy does not affect the garlic α-tocopherol content. (author)

  15. Determination of boron in uranium and aluminium by high pressure liquid chromatography (HPLC)

    International Nuclear Information System (INIS)

    Rao, Radhika M.; Aggarwal, S.K.

    2003-01-01

    Experiments were conducted for the determination of boron in U 3 O 8 powder and aluminium metal using dynamically modified reversed phase high pressure liquid chromatography (RP-HPLC) and using precolumn chromogenic agent viz. curcumin for complexing boron. The complex was separated from the excess of reagent and determined by HPLC. The boron curcumin complex (rosocyanin) was formed after extraction of boron with 2-ethyl-1,3-hexane diol (EHD). Linear calibration curves for boron amounts in the range of 0.02 μg to 0.5 μg were developed and used for the determination of boron in aluminium and uranium samples. (author)

  16. Determination of 1-hydroxypyrene in human urine by high-performance liquid chromatography

    DEFF Research Database (Denmark)

    Hansen, Åse Marie; Poulsen, O M; Christensen, J M

    1993-01-01

    A high-performance liquid chromatography (HPLC)/fluorescence method for quantitative analysis of 1-hydroxypyrene in urine was developed. The method validation analysis showed the method to be in analytical control. No significant systematical errors could be demonstrated. The entire run time....... The developed method is presently used for measurement of 1-hydroxypyrene in urine samples from workers exposed to a low airborne level of polycyclic aromatic hydrocarbons, generally less than 25 micrograms/m3. The urine samples of exposed workers (n = 122) showed a range of 1-hydroxypyrene from the limit...

  17. Increasing flexibility in two-dimensional liquid chromatography by pulsed elution of the first dimension

    DEFF Research Database (Denmark)

    Jakobsen, Simon S.; Christensen, Jan H.; Verdier, Sylvain

    2017-01-01

    This work demonstrates the development of an online two-dimensional liquid chromatography (2D-LC) method where the first dimension column is eluted by a sequence of pulses of increasing eluotropic strength generated by the LC pumps (pulsed-elution 2D-LC). Between the pulses, the first dimension...... online comprehensive 2D-LC: undersampling, difficulties in refocusing, and lack of flexibility in the selection of column dimensions and flow rates because the two dimensions constrain each other. The pulsed-elution 2D-LC was applied for the analysis of a basic fraction of vacuum gas oil. Peak capacity...

  18. Derivatization reagents in liquid chromatography/electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Santa, Tomofumi

    2011-01-01

    Liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) is one of the most prominent analytical techniques owing to its inherent selectivity and sensitivity. In LC/ESI-MS/MS, chemical derivatization is often used to enhance the detection sensitivity. Derivatization improves the chromatographic separation, and enhances the mass spectrometric ionization efficiency and MS/MS detectability. In this review, an overview of the derivatization reagents which have been applied to LC/ESI-MS/MS is presented, focusing on the applications to low molecular weight compounds. 2010 John Wiley & Sons, Ltd.

  19. Denaturing high-performance liquid chromatography mutation analysis in patients with reduced Protein S levels

    DEFF Research Database (Denmark)

    Bathum, Lise; Münster, Anna-Marie; Nybo, Mads

    2008-01-01

    diagnosis and risk estimation. The aim was to design a high-throughput genetic analysis based on denaturing high-performance liquid chromatography to identify sequence variations in the gene coding for Protein S. PATIENTS: In total, 55 patients referred to the Section of Thrombosis and Haemostasis, Odense......BACKGROUND: Patients with congenital Protein S deficiency have increased risk of venous thromboembolism. However, Protein S levels show large intra-individual variation and the biochemical assays have low accuracy and a high interlaboratory variability. Genetic analysis might aid in a more precise......, giving a precise diagnosis and subsequently a better risk estimation....

  20. Determination of limonin and nomilin contents in different citrus cultivars using high performance liquid chromatography

    International Nuclear Information System (INIS)

    Bilal, H.; Hassan, S.; Sahar, S.; Akram, W.; Sahar, S.

    2013-01-01

    High perlorrnance liquid chromatography (HPLC) analysis was done to quantify the amount of limonoids (nomilin and nomilin) in seven selected citrus cultivars. According to the HPLC analysis red blood orange (Citrus sinensis var red blood orange) had maximum amount of limonin (479.77 ug/rnl.), while rough lemon (Citrus jambhiri) had no limonin content. in case of nomonin, rough lemon (Citrus jambhir) had maximum amount of nomilin (54.23 micro g/ML)) while succari (citrus sinensis var succari) had very low amount of nomilin (0.37 micro g/Ml). (author)

  1. Determination of 90SR in food using extraction chromatography and LSC - Liquid Scintillation Counting

    International Nuclear Information System (INIS)

    Temba, Eliane S.C.; Amaral, Angela M.; Reis Junior, Aluisio S.; Monteiro, Roberto P.G.

    2013-01-01

    A methodology for the determination of 90 Sr in food is described. The procedure involved a preliminary freeze-drying of the samples followed by dry-ashing and sample digestion. The separation procedure was carried out using extraction chromatography with Sr Resin, from Eichrom, and 90 Sr was measured by liquid scintillation counting (LSC). A certified reference material, IAEA-375, was analyzed in order to evaluate the reliability of the method, and the results showed good agreement between the measured and certified values. The chemical yield was above 90% and the typical counting efficiency was 82%. The calculated limit of detection was 4.8 x 10 -3 Bq g -1 . (author)

  2. Hb A1c Separation by High Performance Liquid Chromatography in Hemoglobinopathies

    OpenAIRE

    Chandrashekar, Vani

    2016-01-01

    Hb A1c measurement is subject to interference by hemoglobin traits and this is dependent on the method used for determination. In this paper we studied the difference between Hb A1c measured by HPLC in hemoglobin traits and normal chromatograms. We also studied the correlation of Hb A1c with age. Hemoglobin analysis was carried out by high performance liquid chromatography. Spearman's rank correlation was used to study correlation between A1c levels and age. Mann-Whitney U test was used to st...

  3. Chiral separation of pharmaceutical compounds using electrochemically modulated liquid chromatography (EMLC)

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S. [Iowa State Univ., Ames, IA (United States)

    1999-02-12

    This research explores the application of a new technique, termed electrochemically modulated liquid chromatography (EMLC), to the chiral separations of pharmaceutical compounds. The introduction section provides a literature review of the technique and its applications, as well as brief overview of the research described in each of the next two chapters. Chapter 2 investigates the EMLC-based enantiomeric separation of a group of chiral benzodiazepines with β-cyclodextrin as a chiral mobile phase additive. Chapter 3 demonstrates the effects of several experimental parameters on the separation efficiency of drug enantiomers. The author concludes with a general summary and possible directions for future studies. Chapters 2 and 3 are processed separately.

  4. Determination of sulfonamides in meat by liquid chromatography coupled with atmospheric pressure chemical ionization mass spectrometry

    International Nuclear Information System (INIS)

    Kim, Dal Ho; Choi, Jong Oh; Kim, Jin Seog; Lee, Dai Woon

    2002-01-01

    Liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS) has been used for the determination of sulfonamides in meat. Five typical sulfonamides were selected as target compounds, and beef meat was selected as a matrix sample. As internal standards, sulfapyridine and isotope labeled sulfamethazine ( 13 C 6 -SMZ) were used. Compared to the results of recent reports, our results have shown improved precision to a RSD of 1.8% for the determination of sulfamethazine spiked with 75 ng/g level in meat

  5. High-performance liquid chromatography of rat and mouse islet polypeptides

    DEFF Research Database (Denmark)

    Linde, S; Hansen, B; Welinder, B S

    1990-01-01

    After preparative high-performance liquid chromatography of mouse islet culture medium, concentrated on disposable C18 cartridges (Sep-Pak), an unexpected insulin immunoreactive peak eluting earlier than mouse insulin I and II was detected. Molecular mass determination by mass spectrometry...... on the buffer, the organic modifier and the procedure. In particular the use of methanol-trifluoroacetic acid resulted in extensive oxidation. The oxidation could be minimized by adding 2 mM dithiothreitol to the buffer and by degassing and/or nitrogen-bubbling of the buffer. Minimal formation of Met...

  6. Separation and identification of corticosterone metabolites by liquid chromatography--electrospray ionization mass spectrometry.

    Science.gov (United States)

    Miksík, I; Vylitová, M; Pácha, J; Deyl, Z

    1999-04-16

    High-performance liquid chromatography coupled to atmospheric pressure ionization-electrospray ionization mass spectrometry (API-ESI-MS) was investigated for the analysis of corticosterone metabolites; their characterization was obtained by combining the separation on Zorbax Eclipse XDB C18 column (eluted with a methanol-water-acetic acid gradient) with identification using positive ion mode API-ESI-MS and selected ion analysis. The applicability of this method was verified by monitoring the activity of steroid converting enzymes (20beta-hydroxysteroid dehydrogenase and 11beta-hydroxysteroid dehydrogenase) in avian intestines.

  7. Quantification of glibenclamide in cleaning samples of pharmaceutical equipment through high performance liquid chromatography

    International Nuclear Information System (INIS)

    Baeza Fonte, Alen Nils; Diaz Aguila, Elsa Eneida; Martinez Alfonso; Nancy

    2012-01-01

    to submit a selective analytical method for quantization of glibenclamide in cleaning samples of pharmaceutical equipment using high performance liquid chromatography. The mobile phase consisted of an equal mixing of acetonitrile/phosphate buffer KH 2 PO 4 ; with 0.037 mol/L concentration pH 5.25 and flow of 1.5 mL/min, in a Nucleosil 100 C8 column. Glibenclamide was injected with progesterone as internal standard and using an UV detector= 230 nm

  8. A novel multidimensional protein identification technology approach combining protein size exclusion prefractionation, peptide zwitterion-ion hydrophilic interaction chromatography, and nano-ultraperformance RP chromatography/nESI-MS2 for the in-depth analysis of the serum proteome and phosphoproteome: application to clinical sera derived from humans with benign prostate hyperplasia.

    Science.gov (United States)

    Garbis, Spiros D; Roumeliotis, Theodoros I; Tyritzis, Stavros I; Zorpas, Kostas M; Pavlakis, Kitty; Constantinides, Constantinos A

    2011-02-01

    The current proof-of-principle study was aimed toward development of a novel multidimensional protein identification technology (MudPIT) approach for the in-depth proteome analysis of human serum derived from patients with benign prostate hyperplasia (BPH) using rational chromatographic design principles. This study constituted an extension of our published work relating to the identification and relative quantification of potential clinical biomarkers in BPH and prostate cancer (PCa) tissue specimens. The proposed MudPIT approach encompassed the use of three distinct yet complementary liquid chromatographic chemistries. High-pressure size-exclusion chromatography (SEC) was used for the prefractionation of serum proteins followed by their dialysis exchange and solution phase trypsin proteolysis. The tryptic peptides were then subjected to offline zwitterion-ion hydrophilic interaction chromatography (ZIC-HILIC) fractionation followed by their online analysis with reversed-phase nano-ultraperformance chromatography (RP-nUPLC) hyphenated to nanoelectrospray ionization-tandem mass spectrometry using an ion trap mass analyzer. For the spectral processing, the sequential use of the SpectrumMill, Scaffold, and InsPecT software tools was applied for the tryptic peptide product ion MS(2) spectral processing, false discovery rate (FDR) assessment, validation, and protein identification. This milestone serum analysis study allowed the confident identification of over 1955 proteins (p ≤ 0.05; FDR ≤ 5%) with a broad spectrum of biological and physicochemical properties including secreted, tissue-specific proteins spanning approximately 12 orders of magnitude as they occur in their native abundance levels in the serum matrix. Also encompassed in this proteome was the confident identification of 375 phosphoproteins (p ≤ 0.05; FDR ≤ 5%) with potential importance to cancer biology. To demonstrate the performance characteristics of this novel MudPIT approach, a comparison

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

    Science.gov (United States)

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

    2015-06-01

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

  10. Systematic evaluation of matrix effects in hydrophilic interaction chromatography versus reversed phase liquid chromatography coupled to mass spectrometry.

    Science.gov (United States)

    Periat, Aurélie; Kohler, Isabelle; Thomas, Aurélien; Nicoli, Raul; Boccard, Julien; Veuthey, Jean-Luc; Schappler, Julie; Guillarme, Davy

    2016-03-25

    Reversed phase liquid chromatography (RPLC) coupled to mass spectrometry (MS) is the gold standard technique in bioanalysis. However, hydrophilic interaction chromatography (HILIC) could represent a viable alternative to RPLC for the analysis of polar and/or ionizable compounds, as it often provides higher MS sensitivity and alternative selectivity. Nevertheless, this technique can be also prone to matrix effects (ME). ME are one of the major issues in quantitative LC-MS bioanalysis. To ensure acceptable method performance (i.e., trueness and precision), a careful evaluation and minimization of ME is required. In the present study, the incidence of ME in HILIC-MS/MS and RPLC-MS/MS was compared for plasma and urine samples using two representative sets of 38 pharmaceutical compounds and 40 doping agents, respectively. The optimal generic chromatographic conditions in terms of selectivity with respect to interfering compounds were established in both chromatographic modes by testing three different stationary phases in each mode with different mobile phase pH. A second step involved the assessment of ME in RPLC and HILIC under the best generic conditions, using the post-extraction addition method. Biological samples were prepared using two different sample pre-treatments, i.e., a non-selective sample clean-up procedure (protein precipitation and simple dilution for plasma and urine samples, respectively) and a selective sample preparation, i.e., solid phase extraction for both matrices. The non-selective pretreatments led to significantly less ME in RPLC vs. HILIC conditions regardless of the matrix. On the contrary, HILIC appeared as a valuable alternative to RPLC for plasma and urine samples treated by a selective sample preparation. Indeed, in the case of selective sample preparation, the compounds influenced by ME were different in HILIC and RPLC, and lower and similar ME occurrence was generally observed in RPLC vs. HILIC for urine and plasma samples

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

    Energy Technology Data Exchange (ETDEWEB)

    Owens, J; Hok, S; Alcaraz, A; Koester, C

    2008-11-13

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

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

    International Nuclear Information System (INIS)

    Owens, J.; Hok, S.; Alcaraz, A.; Koester, C.

    2008-01-01

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

  13. Use of liquid chromatography for measuring atmospheric sulfur dioxide and nitrogen oxide

    Energy Technology Data Exchange (ETDEWEB)

    Benova, E

    1973-02-01

    A literature search to ascertain the applicability of liquid chromatography to the analysis of atmospheric sulfur dioxide and various oxides of nitrogen is reported. Simple or enriched samples can be analyzed. Plastic bags are recommended for preparation of simple samples; and a table of 18 plastic materials, their manufacturers, and pollutants to which they are inert is provided. Enriched samples can be prepared in chromatographic columns by adsorption methods. Tables are provided listing carriers, stationary phase materials, temperatures, carrier liquids (helium or nitrogen), column dimensions, and other data recommended for chromatographic tests of SO/sub 2/ and NOx. Because of its reactivity and tendency to polymerize, sulfur trioxide should be reduced to SO/sub 2/ prior to analysis.

  14. A simple high performance liquid chromatography method for analyzing paraquat in soil solution samples.

    Science.gov (United States)

    Ouyang, Ying; Mansell, Robert S; Nkedi-Kizza, Peter

    2004-01-01

    A high performance liquid chromatography (HPLC) method with UV detection was developed to analyze paraquat (1,1'-dimethyl-4,4'-dipyridinium dichloride) herbicide content in soil solution samples. The analytical method was compared with the liquid scintillation counting (LSC) method using 14C-paraquat. Agreement obtained between the two methods was reasonable. However, the detection limit for paraquat analysis was 0.5 mg L(-1) by the HPLC method and 0.05 mg L(-1) by the LSC method. The LSC method was, therefore, 10 times more precise than the HPLC method for solution concentrations less than 1 mg L(-1). In spite of the high detection limit, the UC (nonradioactive) HPLC method provides an inexpensive and environmentally safe means for determining paraquat concentration in soil solution compared with the 14C-LSC method.

  15. Novel materials and methods for solid-phase extraction and liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Ambrose, Diana [Iowa State Univ., Ames, IA (United States)

    1997-06-24

    This report contains a general introduction which discusses solid-phase extraction and solid-phase micro-extraction as sample preparation techniques for high-performance liquid chromatography, which is also evaluated in the study. This report also contains the Conclusions section. Four sections have been removed and processed separately: silicalite as a sorbent for solid-phase extraction; a new, high-capacity carboxylic acid functionalized resin for solid-phase extraction; semi-micro solid-phase extraction of organic compounds from aqueous and biological samples; and the high-performance liquid chromatographic determination of drugs and metabolites in human serum and urine using direct injection and a unique molecular sieve.

  16. Screening antiallergic components from Carthamus tinctorius using rat basophilic leukemia 2H3 cell membrane chromatography combined with high-performance liquid chromatography and tandem mass spectrometry.

    Science.gov (United States)

    Han, Shengli; Huang, Jing; Cui, Ronghua; Zhang, Tao

    2015-02-01

    Carthamus tinctorius, used in traditional Chinese medicine, has many pharmacological effects, such as anticoagulant effects, antioxidant effects, antiaging effects, regulation of gene expression, and antitumor effects. However, there is no report on the antiallergic effects of the components in C. tinctorius. In the present study, we investigated the antiallergic components of C. tinctorius and its mechanism of action. A rat basophilic leukemia 2H3/cell membrane chromatography coupled online with high-performance liquid chromatography and tandem mass spectrometry method was developed to screen antiallergic components from C. tinctorius. The screening results showed that Hydroxysafflor yellow A, from C. tinctorius, was the targeted component that retained on the rat basophilic leukemia 2H3/cell membrane chromatography column. We measured the amount of β-hexosaminidase and histamine released in mast cells and the key markers of degranulation. The release assays showed that Hydroxysafflor yellow A could attenuate the immunoglobulin E induced release of allergic cytokines without affecting cell viability from 1.0 to 50.0 μM. In conclusion, the established rat basophilic leukemia 2H3 cell membrane chromatography coupled with online high-performance liquid chromatography and tandem mass spectrometry method successfully screened and identified Hydroxysafflor yellow A from C. tinctorius as a potential antiallergic component. Pharmacological analysis elucidated that Hydroxysafflor yellow A is an effective natural component for inhibiting immunoglobulin E-antigen-mediated degranulation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    Science.gov (United States)

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

    2016-04-01

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

  18. Purification of lignans from Fructus Arctii using off-line two-dimensional supercritical fluid chromatography/reversed-phase liquid chromatography.

    Science.gov (United States)

    Yang, Bichao; Xin, Huaxia; Wang, Feier; Cai, Jianfeng; Liu, Yanfang; Fu, Qing; Jin, Yu; Liang, Xinmiao

    2017-08-01

    As a common traditional Chinese medicine, Fructus Arctii has important clinical medical values. Its main components are lignans, which are difficult to separate and analyze because of the complex composition, similar chemical structures, and close properties. In this study, an off-line two-dimensional supercritical fluid chromatography/reversed-phase liquid chromatography method, as well as an effective sample pretreatment method based on hydrophilic interaction chromatography material, was developed to enrich the minor lignan fractions and obtain high-purity compounds. In total, 12 high-purity compounds were isolated from Fructus Arctii. Their structures were identified by using high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy, which showed that all were lignans and that most of them were isomers. The results demonstrated the effective off-line two-dimensional supercritical fluid chromatography/reversed-phase liquid chromatography method for the purification of lignans from Fructus Arctii. The separation protocol established here will be beneficial for the separation of complex samples from other kinds of natural products. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Quantification of steroid hormones in human serum by liquid chromatography-high resolution tandem mass spectrometry.

    Science.gov (United States)

    Matysik, Silke; Liebisch, Gerhard

    2017-12-01

    A limited specificity is inherent to immunoassays for steroid hormone analysis. To improve selectivity mass spectrometric analysis of steroid hormones by liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been introduced in the clinical laboratory over the past years usually with low mass resolution triple-quadrupole instruments or more recently by high resolution mass spectrometry (HR-MS). Here we introduce liquid chromatography-high resolution tandem mass spectrometry (LC-MS/HR-MS) to further increase selectivity of steroid hormone quantification. Application of HR-MS demonstrates an enhanced selectivity compared to low mass resolution. Separation of isobaric interferences reduces background noise and avoids overestimation. Samples were prepared by automated liquid-liquid extraction with MTBE. The LC-MS/HR-MS method using a quadrupole-Orbitrap analyzer includes eight steroid hormones i.e. androstenedione, corticosterone, cortisol, cortisone, 11-deoxycortisol, 17-hydroxyprogesterone, progesterone, and testosterone. It has a run-time of 5.3min and was validated according to the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) guidelines. For most of the analytes coefficient of variation were 10% or lower and LOQs were determined significantly below 1ng/ml. Full product ion spectra including accurate masses substantiate compound identification by matching their masses and ratios with authentic standards. In summary, quantification of steroid hormones by LC-MS/HR-MS is applicable for clinical diagnostics and holds also promise for highly selective quantification of other small molecules. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Simultaneous drug identification in urine of sexual assault victims by using liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Lee, Hei Hwa; Chen, Suen Chi; Lee, Jong Feng; Lin, Hsin Yu; Chen, Bai Hsiun

    2018-01-01

    According to domestic and international epidemiological investigation, the proportion of substance involved sexual assault has the trend of ascent. In the past, laboratory methods that investigated urine sample of the sexual assault victims was to screen with enzyme immunoassay and then confirmed with mass spectrometry. The objective of the study is to simultaneously identify abused drugs in 126 decoded urine samples of sexual assault victims by liquid chromatography tandem mass spectrometry. The instrument was operated in multiple-reaction monitoring with an electro-spray positive ionization mode. Chromatograms were separated with ACE5 C18 column on a gradient of acetonitrile. After liquid-liquid extraction, samples were passed through a 0.22μm PVDF filter before injection into the system. The limits of quantitation ranged from 0.2 to 10ng/mL. The precision (CV) results were below 12.9% (intraday) and 15.0% (interday). The intraday accuracy ranged from 84.8 to 121.0%, interday accuracy ranged from 72.0 to 117.3%. We found that 29 (23.0%) were positive for drugs. The most common drug identified is flunitrazepam (11.1%), followed by nimetazepam and ketamine (7.9%), some new psychoactive substances, such as 2C-B, mephedrone, methylone, PMA and PMMA were also identified. We identified abused drugs, benzodiazepines, and new psychoactive substances in urine of sexual assault victims by using liquid chromatography tandem mass spectrometry. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Carbon nanoparticles from corn stalk soot and its novel application as stationary phase of hydrophilic interaction chromatography and per aqueous liquid chromatography

    International Nuclear Information System (INIS)

    Li Yuanyuan; Xu Luan; Chen Tong; Liu Xiaoyan; Xu Zhigang; Zhang Haixia

    2012-01-01

    Highlights: ► Carbon nanoparticles (6–18 nm in size) were prepared from corn stalk soot. ► CNPs-based silica were used as novel chromatography stationary phase. ► The new phase shows good separation selectivity for polar compounds. ► The new phase had the similar retention for polar probes in HILIC and PALC modes. ► In contrast to PALC, under HILIC conditions high efficiencies were achieved. - Abstract: Carbon nanoparticles (CNPs) (6–18 nm in size) were prepared by refluxing corn stalk soot in nitric acid. The obtained acid-oxidized CNPs are soluble in water due to the existence of carboxylic and hydroxyl groups. 13 C NMR measurement shows the CNPs are mainly of sp 2 and sp 3 carbon structure different from CNPs obtained from candle soot and natural gas soot. Furthermore, these CNPs exhibit unique photoluminescence properties. Interestingly, the CNPs might be exploited to immobilize on the surface of porous silica particles as chromatographic stationary phase. The resultant packing material was evaluated by high-performance liquid chromatography, indicating that the new stationary phase could be used in hydrophilic interaction liquid chromatography (HILIC) and per aqueous liquid chromatography (PALC) modes. The separation of five nucleosides, four sulfa compounds and safflower injection was achieved by using the new column in the HILIC and PALC modes, respectively.

  2. Quantification of Quercetin and Rutin from Benincasa hispida Seeds and Carissa Congesta Roots by High-performance Thin Layer Chromatography and High-performance Liquid Chromatography.

    Science.gov (United States)

    Doshi, Gaurav Mahesh; Une, Hemant Devidas

    2016-01-01

    In Indian Ayurvedic system, Benincasa hispida (BH) and Carissa congesta (CC) are well-known plants used for major and minor ailments. BH has been regarded as Kushmanda, whereas CC has been used in immune-related disorders of the human system. Quercetin and rutin identified from the vast plethora of plant extracts have proved to possess ethnopharmacological relevance. In present studies, we have determined quercetin and rutin in terms of percentage in BH seeds and CC roots by high-performance thin layer chromatography (HPTLC) and high-performance liquid chromatography (HPLC). After extraction and phytochemical screening, the extracts were subjected to quantification for the presence of quercetin and rutin by HPTLC and HPLC. HPTLC showed quercetin as 44.60, 27.13% and rutin as 32.00, 36.31% w/w, whereas HPLC revealed quercetin as 34.00, 35.00% and rutin as 21.99, 45.03% w/v in BH and CC extracts, respectively. The BH and CC extracts have elucidated peaks that were corresponding with standard peaks on undertaking chromatographic studies. Quercetin and rutin are isolated from BH seeds and CC roots by High Performance. Thin Layer Chromatography and High Performance Liquid Chromatography. HPTLC revealed presence of quercetin as 44.60, 27.13 % and rutin as 32.00, 36.31 % w/w. HPLC revealed presence of quercetin as 34.00, 35.00 % and rutin as 21.99, 45.03 % w/v. Abbreviation Used: HPTLC: High Performance Thin Layer Chromatography; HPLC: High Pressure Liquid Chromatography, UV: Ultraviolet, CC: Carissa congesta, BH: Benincasa hispida.

  3. Quantification of Quercetin and Rutin from Benincasa hispida Seeds and Carissa Congesta Roots by High-performance Thin Layer Chromatography and High-performance Liquid Chromatography

    Science.gov (United States)

    Doshi, Gaurav Mahesh; Une, Hemant Devidas

    2016-01-01

    Objective: In Indian Ayurvedic system, Benincasa hispida (BH) and Carissa congesta (CC) are well-known plants used for major and minor ailments. BH has been regarded as Kushmanda, whereas CC has been used in immune-related disorders of the human system. Quercetin and rutin identified from the vast plethora of plant extracts have proved to possess ethnopharmacological relevance. Materials and Methods: In present studies, we have determined quercetin and rutin in terms of percentage in BH seeds and CC roots by high-performance thin layer chromatography (HPTLC) and high-performance liquid chromatography (HPLC). After extraction and phytochemical screening, the extracts were subjected to quantification for the presence of quercetin and rutin by HPTLC and HPLC. Results: HPTLC showed quercetin as 44.60, 27.13% and rutin as 32.00, 36.31% w/w, whereas HPLC revealed quercetin as 34.00, 35.00% and rutin as 21.99, 45.03% w/v in BH and CC extracts, respectively. Conclusion: The BH and CC extracts have elucidated peaks that were corresponding with standard peaks on undertaking chromatographic studies. SUMMARY Quercetin and rutin are isolated from BH seeds and CC roots by High Performance. Thin Layer Chromatography and High Performance Liquid Chromatography. HPTLC revealed presence of quercetin as 44.60, 27.13 % and rutin as 32.00, 36.31 % w/w. HPLC revealed presence of quercetin as 34.00, 35.00 % and rutin as 21.99, 45.03 % w/v. Abbreviation Used: HPTLC: High Performance Thin Layer Chromatography; HPLC: High Pressure Liquid Chromatography, UV: Ultraviolet, CC: Carissa congesta, BH: Benincasa hispida PMID:26941534

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

    Science.gov (United States)

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

    2016-12-01

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

  5. Identification of aroma-active volatiles in banana Terra spirit using multidimensional gas chromatography with simultaneous mass spectrometry and olfactometry detection.

    Science.gov (United States)

    Capobiango, Michely; Mastello, Raíssa Bittar; Chin, Sung-Tong; Oliveira, Evelyn de Souza; Cardeal, Zenilda de Lourdes; Marriott, Philip John

    2015-04-03

    Fruit spirits have been produced and consumed throughout the world for centuries. However, the aroma composition of banana spirits is still poorly characterised. We have investigated the aroma-impact compounds of the banana Terra spirit for the first time, using multidimensional gas chromatography (MDGC and GC × GC) in a multi-hyphenated system - i.e., coupled to flame ionisation detection (FID), mass spectrometry (MS), and olfactometry (O). Solid-phase microextraction (SPME) was used to isolate the headspace aroma compounds of the banana spirit. The detection frequency (DF) technique was applied and aroma regions, detected in the first column separation at >60% Nasal Impact Frequency (NIF), were screened as target potent odour regions in the sample. Using a polar/non-polar phase column set, the potent odour regions were further subjected to MDGC separation with simultaneous O and MS detection for correlation of the aroma perception with MS data for individual resolved aroma-impact compounds. GC-O analysis enabled 18 aroma-impact regions to be located as providing volatiles of interest for further study; for example, those comprising perceptions of flower, whisky, green, amongst others. Compounds were tentatively identified through MS data matching and retention indices in both first and second dimensions. The principal volatile compounds identified in this work, which are responsible for the characteristic aroma of the banana spirit, are 3-methylbutan-1-ol, 3-methylbutan-1-ol acetate, 2-phenylethyl acetate and phenylethyl alcohol. This is the first such study to reveal the major aroma compounds that contribute to banana spirit aroma. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. A high pressure liquid chromatography method for separation of prolactin forms.

    Science.gov (United States)

    Bell, Damon A; Hoad, Kirsten; Leong, Lillian; Bakar, Juwaini Abu; Sheehan, Paul; Vasikaran, Samuel D

    2012-05-01

    Prolactin has multiple forms and macroprolactin, which is thought not to be bioavailable, can cause a raised serum prolactin concentration. Gel filtration chromatography (GFC) is currently the gold standard method for separating macroprolactin, but is labour-intensive. Polyethylene glycol (PEG) precipitation is suitable for routine use but may not always be accurate. We developed a high pressure liquid chromatography (HPLC) assay for macroprolactin measurement. Chromatography was carried out using an Agilent Zorbax GF-250 (9.4 × 250 mm, 4 μm) size exclusion column and 50 mmol/L Tris buffer with 0.15 mmol/L NaCl at pH 7.2 as mobile phase, with a flow rate of 1 mL/min. Serum or plasma was diluted 1:1 with mobile phase and filtered and 100 μL injected. Fractions of 155 μL were collected for prolactin measurement and elution profile plotted. The area under the curve of each prolactin peak was calculated to quantify each prolactin form, and compared with GFC. Clear separation of monomeric-, big- and macroprolactin forms was achieved. Quantification was comparable to GFC and precision was acceptable. Total time from injection to collection of the final fraction was 16 min. We have developed an HPLC method for quantification of macroprolactin, which is rapid and easy to perform and therefore can be used for routine measurement.

  7. Enhanced fluidity liquid chromatography of inulin fructans using ternary solvent strength and selectivity gradients.

    Science.gov (United States)

    Bennett, Raffeal; Olesik, Susan V

    2018-01-25

    The value of exploring selectivity and solvent strength ternary gradients in enhanced fluidity liquid chromatography (EFLC) is demonstrated for the separation of inulin-type fructans from chicory. Commercial binary pump systems for supercritical fluid chromatography only allow for the implementation of ternary solvent strength gradients which can be restrictive for the separation of polar polymeric analytes. In this work, a custom system was designed to extend the capability of EFLC to allow tuning of selectivity or solvent strength in ternary gradients. Gradient profiles were evaluated using the Berridge function (RF 1 ), normalized resolution product (NRP), and gradient peak capacity (P c ). Selectivity gradients provided the separation of more analytes over time. The RF 1 function showed favor to selectivity gradients with comparable P c to that of solvent strength gradients. NRP did not strongly correlate with P c or RF 1 score. EFLC with the hydrophilic interaction chromatography, HILIC, separation mode was successfully employed to separate up to 47 fructan analytes in less than 25 min using a selectivity gradient. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Simultaneous determination of ramipril, ramiprilat and telmisartan in human plasma using liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Gupta, V K; Jain, Rajeev; Lukram, Ojitkumar; Agarwal, Shilpi; Dwivedi, Ashish

    2011-01-15

    A rapid and sensitive liquid chromatography tandem mass spectrometry method has been developed and validated for the simultaneous determination of ramipril, ramiprilat and telmisartan in human plasma. The solid-phase extraction technique was used for the extraction of ramipril, ramiprilat and telmisartan from human plasma. Trandolaprilat and hydrochlorothiazide were used as the internal standards (ISs). Chromatography was performed on a Hypurity C18, 5 μm, 50 mm × 4.6mm column, with the mobile phase consisting of ammonium acetate and acetonitrile (in a 20:80 ratio), followed by detection using mass spectrometry. The method involves a simple reversed isocratic chromatography condition and mass spectrometry detection, which enables detection at sub-nanogram levels. The method was validated and the lower limit of quantification for ramipril, ramiprilat and telmisartan was found to be 0.1 ng mL(-1), 0.1 ng mL(-1) and 2 ng mL(-1), respectively. The mean recovery for ramipril, ramiprilat and telmisartan ranged from 90.1 to 104.1%. This method increased the sensitivity and selectivity; resulting in high-throughput analysis of ramipril, ramiprilat and telmisartan using two different ISs in a single experiment for bioequivalence studies, with a chromatographic run time of 1.5 min only. Copyright © 2010 Elsevier B.V. All rights reserved.

  9. State-of-the art of selective detection and identification of I-, Br-, Cl-, and F-containing compounds in gas chromatography and liquid chromatography.

    Science.gov (United States)

    Brede, Cato; Pedersen-Bjergaard, Stig

    2004-09-24

    This review article presents an overview of halogen-specific detection in gas chromatography (GC) and liquid chromatography (LC). Attention is primarily focused on the use of plasma emission spectroscopy and plasma mass spectrometry as detectors, but other halogen-selective detection principles are also mentioned. Different instrumental configurations are discussed both with respect to technical set-up and performance, the principal reasons for halogen-selective detection are highlighted, and recent applications are reviewed from areas such as environmental chemistry, petroleum characterization, and drug analysis.

  10. Development and application of liquid chromatography coupled to isotope ratio mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lijun

    2014-02-19

    Stable isotope analysis has found widespread applications in various disciplines such as archaeology, geochemistry, biology, food authenticity, and forensic science. Coupling chromatography to isotope ratio mass spectrometry for compound-specific isotope analysis (CSIA) is a trend, as it provides several advantages over bulk isotope analysis, e.g., relatively simple sample preparation, the ability to measure individual compounds in a complex mixture in one run, and the reduced sample size required for precise isotope analysis. Gas chromatography coupled to isotope ratio mass spectrometry (GC/IRMS) has been well-established for compound-specific isotope analysis of volatile organic compounds within the last two decades. However, an interface combining liquid chromatography with isotope ratio mass spectrometry (LC/IRMS) was not commercially available until 2004. The current design of the interface requires using a carbon-free eluent in chromatographic separation. This requirement limits the application of the most frequently used reversed-phase liquid chromatography in CSIA, because the elution strength of water at room temperature is too low to serve as mobile phase in reversed-phase separations. In order to increase the elution strength of water, we propose using high temperature water for chromatographic elution. The polarity of water decreases with an increase of temperature, yielding increased elution strength in reversed-phase columns. Therefore, high temperature water can be used as eluent instead of organic solvent for combining reversed-phase liquid chromatography with isotope ratio mass spectrometry (RPLC/IRMS). Additionally, temperature gradients can replace organic solvent gradients to increase chromatographic resolution. This is very important for LC/IRMS analysis, as precise isotope analysis requires baseline separation of analytes. In this thesis, high-temperature reversed-phase liquid chromatography was coupled to, and for the first time carefully

  11. Development and application of liquid chromatography coupled to isotope ratio mass spectrometry

    International Nuclear Information System (INIS)

    Zhang, Lijun

    2014-01-01

    Stable isotope analysis has found widespread applications in various disciplines such as archaeology, geochemistry, biology, food authenticity, and forensic science. Coupling chromatography to isotope ratio mass spectrometry for compound-specific isotope analysis (CSIA) is a trend, as it provides several advantages over bulk isotope analysis, e.g., relatively simple sample preparation, the ability to measure individual compounds in a complex mixture in one run, and the reduced sample size required for precise isotope analysis. Gas chromatography coupled to isotope ratio mass spectrometry (GC/IRMS) has been well-established for compound-specific isotope analysis of volatile organic compounds within the last two decades. However, an interface combining liquid chromatography with isotope ratio mass spectrometry (LC/IRMS) was not commercially available until 2004. The current design of the interface requires using a carbon-free eluent in chromatographic separation. This requirement limits the application of the most frequently used reversed-phase liquid chromatography in CSIA, because the elution strength of water at room temperature is too low to serve as mobile phase in reversed-phase separations. In order to increase the elution strength of water, we propose using high temperature water for chromatographic elution. The polarity of water decreases with an increase of temperature, yielding increased elution strength in reversed-phase columns. Therefore, high temperature water can be used as eluent instead of organic solvent for combining reversed-phase liquid chromatography with isotope ratio mass spectrometry (RPLC/IRMS). Additionally, temperature gradients can replace organic solvent gradients to increase chromatographic resolution. This is very important for LC/IRMS analysis, as precise isotope analysis requires baseline separation of analytes. In this thesis, high-temperature reversed-phase liquid chromatography was coupled to, and for the first time carefully

  12. Determination of thiopurine S-methyltransferase activity by hydrophilic interaction liquid chromatography hyphenated with mass spectrometry.

    Science.gov (United States)

    Pecher, Daniel; Dokupilová, Svetlana; Zelinková, Zuzana; Peppelenbosch, Maikel; Mikušová, Veronika; Mikuš, Peter

    2017-08-05

    Thiopurine S-methyltransferase (TPMT) plays an important role in the metabolism of thiopurines used in the therapy of inflammatory bowel diseases (IBD). In this work a new progressive method for the determination of TPMT activity in red blood cells lysates was developed. Analysis was carried out by means of hydrophilic interaction liquid chromatography (HILIC) hyphenated with mass spectrometry (MS). In comparison with reversed-phase high-performance liquid chromatography (RP-HPLC), that has been typically applied in determination of TPMT activity, the HILIC significantly improved the analytical signal provided by MS, shortened analysis time, and improved chromatographic resolution. The HILIC-HPLC-MS method was optimized and validated, providing favorable parameters of detection and quantitation limits (5.5 and 16.5pmol/mL, respectively), linearity (coefficient of determination 0.9999 in the range of 0.01-1.0nmol/mL), recovery and precision (93.25-100.37% with RSD 1.06-1.32% in the whole concentration range of QC samples). Moreover, in contrast to the conventional RP-HPLC-UV approach, the complex phenotype TPMT profiles can be reliably and without interferences monitored using the HILIC-HPLC-MS method. Such advanced monitoring can provide valuable detail information on the thiopurines (e.g. evaluating ratio of methylated and non-methylated 6-mercaptopurine) and, by that, TPMT action in biological systems before and during the therapy of IBD. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. DETECTION AND QUANTIFICATION OF PHYTOCHEMICAL MARKERS OF Ilex paraguariensis BY LIQUID CHROMATOGRAPHY

    Directory of Open Access Journals (Sweden)

    Rodrigo M. C. Pinto

    2015-11-01

    Full Text Available Ilex paraguariensis (yerba-mate is used as a beverage, and its extract requires adequate quality control methods in order to guarantee quality and safe use. Strategies to develop and optimize a chromatographic method to quantify theobromine, caffeine, and chlorogenic acid in I. paraguariensis extracts were evaluated by applying a quality by design (QbD model and ultra high-performance liquid chromatography (UHPLC. The presence of these three phytochemical markers in the extracts was evaluated using UHPLC-MS and was confirmed by the chromatographic bands in the total ion current traces (m/z of 181.1 [M+H]+, 195.0 [M+H]+, and 353.0 [M−H]−, respectively. The developed method was then transferred to a high-performance liquid chromatography (HPLC platform, and the three phytochemical markers were used as external standards in the validation of a method for analyses of these compounds in extracts using a diode array detector (DAD. The validated method was applied to quantify the chlorogenic acid, caffeine, and theobromine in the samples. HPLC-DAD chromatographic fingerprinting was also used in a multivariate approach to process the entire data and to separate the I. paraguariensis extracts into two groups. The developed method is very useful for qualifying and quantifying I. paraguariensis extracts.

  14. Core-shell microspheres with porous nanostructured shells for liquid chromatography.

    Science.gov (United States)

    Ahmed, Adham; Skinley, Kevin; Herodotou, Stephanie; Zhang, Haifei

    2018-01-01

    The development of new stationary phases has been the key aspect for fast and efficient high-performance liquid chromatography separation with relatively low backpressure. Core-shell particles, with a solid core and porous shell, have been extensively investigated and commercially manufactured in the last decade. The excellent performance of core-shell particles columns has been recorded for a wide range of analytes, covering small and large molecules, neutral and ionic (acidic and basic), biomolecules and metabolites. In this review, we first introduce the advance and advantages of core-shell particles (or more widely known as superficially porous particles) against non-porous particles and fully porous particles. This is followed by the detailed description of various methods used to fabricate core-shell particles. We then discuss the applications of common silica core-shell particles (mostly commercially manufactured), spheres-on-sphere particles and core-shell particles with a non-silica shell. This review concludes with a summary and perspective on the development of stationary phase materials for high-performance liquid chromatography applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Analysis of glyphosate residues in cereals using liquid chromatography-mass spectrometry (LC-MS/MS)

    DEFF Research Database (Denmark)

    Granby, Kit; Johannesen, S.; Gabrielsen, Martin Vahl

    2003-01-01

    A fast and specific method for the determination of glyphosate in cereals is described. The method is based on extraction with water by ultrasonication. The samples are cleaned up and separated by high-performance liquid chromatography on a polystyrene-based reverse-phase column (clean-up) in ser......A fast and specific method for the determination of glyphosate in cereals is described. The method is based on extraction with water by ultrasonication. The samples are cleaned up and separated by high-performance liquid chromatography on a polystyrene-based reverse-phase column (clean...... monitored m/z 168--> 150 (glyphosate) and 170-->152 (internal standard 2- 13 (CN)-N-15-glyphosate) for quantification. The mean recovery was 85% ( n =32) at spiking levels from 0.03 to 0.33 mg kg(-1) . From 1998 to 2001, from the analysis of about 50 samples per annum, a reduction in the glyphosate residues...... was observed owing to a Danish trade decision not to use grain with glyphosate residues for milling or bread production....

  16. [Rapid determination of 8 urinary carbamate pesticides by liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Liu, Hualiang; Wang, Yuan; Zhu, Baoli

    2015-11-01

    To establish a method for simultaneously determining the urinary concentrations of 8 carbamate pesticides. After being purified by acetonitrile precipitation, urine samples were transferred to a liquid chromatography-tandem mass spectrometry system, and the concentrations of 8 carbamate pesticides were determined by external standard method. A C18 column was used for ultra-high-performance liquid chromatography; methanol/ammonium acetate solution was used as the mobile phase for gradient elution; the mass spectrometer was operated in a multi-reaction monitoring mode. The calibration curves were linear when the urinary concentrations of these carbamate pesticides were 20~800 µg/L, and the recovery rates were 61.0%~121% at spiked levels of 20, 200 and 800 µg/L, with a relative standard deviation of 1.7%~5.5%. This determination method meets the Guide for establishing occupational health standards-part 5: Determination methods of chemicals in biological materials, and can be used for simultaneous determination of 8 carbamate pesticides in the urine of poisoning patients.

  17. High-throughput, Highly Sensitive Analyses of Bacterial Morphogenesis Using Ultra Performance Liquid Chromatography*

    Science.gov (United States)

    Desmarais, Samantha M.; Tropini, Carolina; Miguel, Amanda; Cava, Felipe; Monds, Russell D.; de Pedro, Miguel A.; Huang, Kerwyn Casey

    2015-01-01

    The bacterial cell wall is a network of glycan strands cross-linked by short peptides (peptidoglycan); it is responsible for the mechanical integrity of the cell and shape determination. Liquid chromatography can be used to measure the abundance of the muropeptide subunits composing the cell wall. Characteristics such as the degree of cross-linking and average glycan strand length are known to vary across species. However, a systematic comparison among strains of a given species has yet to be undertaken, making it difficult to assess the origins of variability in peptidoglycan composition. We present a protocol for muropeptide analysis using ultra performance liquid chromatography (UPLC) and demonstrate that UPLC achieves resolution comparable with that of HPLC while requiring orders of magnitude less injection volume and a fraction of the elution time. We also developed a software platform to automate the identification and quantification of chromatographic peaks, which we demonstrate has improved accuracy relative to other software. This combined experimental and computational methodology revealed that peptidoglycan composition was approximately maintained across strains from three Gram-negative species despite taxonomical and morphological differences. Peptidoglycan composition and density were maintained after we systematically altered cell size in Escherichia coli using the antibiotic A22, indicating that cell shape is largely decoupled from the biochemistry of peptidoglycan synthesis. High-throughput, sensitive UPLC combined with our automated software for chromatographic analysis will accelerate the discovery of peptidoglycan composition and the molecular mechanisms of cell wall structure determination. PMID:26468288

  18. Determination of Urine Albumin by New Simple High-Performance Liquid Chromatography Method.

    Science.gov (United States)

    Klapkova, Eva; Fortova, Magdalena; Prusa, Richard; Moravcova, Libuse; Kotaska, Karel

    2016-11-01

    A simple high-performance liquid chromatography (HPLC) method was developed for the determination of albumin in patients' urine samples without coeluting proteins and was compared with the immunoturbidimetric determination of albumin. Urine albumin is important biomarker in diabetic patients, but part of it is immuno-nonreactive. Albumin was determined by high-performance liquid chromatography (HPLC), UV detection at 280 nm, Zorbax 300SB-C3 column. Immunoturbidimetric analysis was performed using commercial kit on automatic biochemistry analyzer COBAS INTEGRA ® 400, Roche Diagnostics GmbH, Manheim, Germany. The HLPC method was fully validated. No significant interference with other proteins (transferrin, α-1-acid glycoprotein, α-1-antichymotrypsin, antitrypsin, hemopexin) was found. The results from 301 urine samples were compared with immunochemical determination. We found a statistically significant difference between these methods (P = 0.0001, Mann-Whitney test). New simple HPLC method was developed for the determination of urine albumin without coeluting proteins. Our data indicate that the HPLC method is highly specific and more sensitive than immunoturbidimetry. © 2016 Wiley Periodicals, Inc.

  19. Validation of a technique by high-performance liquid chromatography for the determination of total isoflavones

    Directory of Open Access Journals (Sweden)

    Pilar A. Soledispa Cañarte

    2017-04-01

    Full Text Available Context: Isoflavones may act as selective regulators in the prevention of various diseases. The most important source of isoflavones is the soy, from which different phytotherapeutics are elaborated of use in Ecuadorian population. However, its concentration varies depending on several factors, therefore quality assessment need to be carried out through out several analytical methods. Aims: To validate an analytical method by high precision liquid chromatography (HPLC to quantify total isoflavones in herbal medicine. Methods: To quantify isoflavones, it was used a brand liquid chromatography with UV/VIS detector at 260 nm, C-18 column using isocratic method. The mobile phase was composed of 2% acetic acid: acetonitrile (75:25. The quantification was performed against reference standard. The parameters for the validation followed the established in the USP 33. Results: The chromatogram presented six peaks with elution between 1.557 and 18.913 min. The linearity of the system and the method got r2 equal to 0.98 and 0.99 respectively. The coefficients of variation 1.5% in the study of repetitiveness and 2% in intermediate precision. The accuracy of the adjusted lineal model exhibited r=0.95 and intercept reliable interval (-0.921; 1.743. Conclusions: The validated method was specific, accurate, precise and linear. It can be used for quality control and stability studies of isoflavones present in herbal medicine.

  20. Targeted liquid chromatography tandem mass spectrometry to quantitate wheat gluten using well-defined reference proteins

    Science.gov (United States)

    Schalk, Kathrin; Koehler, Peter

    2018-01-01

    Celiac disease (CD) is an inflammatory disorder of the upper small intestine caused by the ingestion of storage proteins (prolamins and glutelins) from wheat, barley, rye, and, in rare cases, oats. CD patients need to follow a gluten-free diet by consuming gluten-free products with gluten contents of less than 20 mg/kg. Currently, the recommended method for the quantitative determination of gluten is an enzyme-linked immunosorbent assay (ELISA) based on the R5 monoclonal antibody. Because the R5 ELISA mostly detects the prolamin fraction of gluten, a new independent method is required to detect prolamins as well as glutelins. This paper presents the development of a method to quantitate 16 wheat marker peptides derived from all wheat gluten protein types by liquid chromatography tandem mass spectrometry (LC-MS/MS) in the multiple reaction monitoring mode. The quantitation of each marker peptide in the chymotryptic digest of a defined amount of the respective reference wheat protein type resulted in peptide-specific yields. This enabled the conversion of peptide into protein type concentrations. Gluten contents were expressed as sum of all determined protein type concentrations. This new method was applied to quantitate gluten in wheat starches and compared to R5 ELISA and gel-permeation high-performance liquid chromatography with fluorescence detection (GP-HPLC-FLD), which resulted in a strong correlation between LC-MS/MS and the other two methods. PMID:29425234

  1. Targeted liquid chromatography tandem mass spectrometry to quantitate wheat gluten using well-defined reference proteins.

    Directory of Open Access Journals (Sweden)

    Kathrin Schalk

    Full Text Available Celiac disease (CD is an inflammatory disorder of the upper small intestine caused by the ingestion of storage proteins (prolamins and glutelins from wheat, barley, rye, and, in rare cases, oats. CD patients need to follow a gluten-free diet by consuming gluten-free products with gluten contents of less than 20 mg/kg. Currently, the recommended method for the quantitative determination of gluten is an enzyme-linked immunosorbent assay (ELISA based on the R5 monoclonal antibody. Because the R5 ELISA mostly detects the prolamin fraction of gluten, a new independent method is required to detect prolamins as well as glutelins. This paper presents the development of a method to quantitate 16 wheat marker peptides derived from all wheat gluten protein types by liquid chromatography tandem mass spectrometry (LC-MS/MS in the multiple reaction monitoring mode. The quantitation of each marker peptide in the chymotryptic digest of a defined amount of the respective reference wheat protein type resulted in peptide-specific yields. This enabled the conversion of peptide into protein type concentrations. Gluten contents were expressed as sum of all determined protein type concentrations. This new method was applied to quantitate gluten in wheat starches and compared to R5 ELISA and gel-permeation high-performance liquid chromatography with fluorescence detection (GP-HPLC-FLD, which resulted in a strong correlation between LC-MS/MS and the other two methods.

  2. Separation of lanthanum from nuclear fuel solutions by high performance liquid chromatography

    International Nuclear Information System (INIS)

    Lazar, G. C.; Petre, M.; Androne, G.; Benga, A.

    2016-01-01

    This paper presents the separation of uranium, praseodymium and lanthanum from nuclear fuel solutions by high performance liquid chromatography (HPLC). The aim of this study is to establish a minimum concentration of lanthanum which can be analyzed by high performance liquid chromatography, and also to study the effect of uranium concentration on the separation of praseodymium and lanthanum. Optimum gradient mode was established for mixture standard stoc solutions with uranium in a concentration of 1 mg/ml, praseodymium and lanthanum in a concentration range of 1-5 μg/ml from each element. These conditions were applied for the separation of lanthanum from a nuclear fuel solution in which praseodymium and lanthanum were added in a concentration of 3 μg/ml from each element. The elution behavior of lanthanum as a function of the pH and the concentration of the mobile phase, using a mixture of 1-octanesulfonic acid sodium salt with a-hidroxyisobutiric acid is presented. (authors)

  3. Neutral monosaccharide composition analysis of plant-derived oligo- and polysaccharides by high performance liquid chromatography.

    Science.gov (United States)

    Yan, Jun; Shi, Songshan; Wang, Hongwei; Liu, Ruimin; Li, Ning; Chen, Yonglin; Wang, Shunchun

    2016-01-20

    A novel analytical method for neutral monosaccharide composition analysis of plant-derived oligo- and polysaccharides was developed using hydrophilic interaction liquid chromatography coupled to a charged aerosol detector. The effects of column type, additives, pH and column temperature on retention and separation were evaluated. Additionally, the method could distinguish potential impurities in samples, including chloride, sulfate and sodium, from sugars. The results of validation demonstrated that this method had good linearity (R(2) ≥ 0.9981), high precision (relative standard deviation ≤ 4.43%), and adequate accuracy (94.02-103.37% recovery) and sensitivity (detection limit: 15-40 ng). Finally, the monosaccharide compositions of the polysaccharide from Eclipta prostrasta L. and stachyose were successfully profiled through this method. This report represents the first time that all of these common monosaccharides could be well-separated and determined simultaneously by high performance liquid chromatography without additional derivatization. This newly developed method is convenient, efficient and reliable for monosaccharide analysis. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Isotope ratio mass spectrometry coupled to liquid and gas chromatography for wine ethanol characterization.

    Science.gov (United States)

    Cabañero, Ana I; Recio, Jose L; Rupérez, Mercedes

    2008-10-01

    Two new procedures for wine ethanol 13C/12C isotope ratio determination, using high-performance liquid chromatography and gas chromatography isotope ratio mass spectrometry (HPLC/IRMS and GC/IRMS), have been developed to improve isotopic methods dedicated to the study of wine authenticity. Parameters influencing separation of ethanol from wine matrix such as column, temperature, mobile phase, flow rates and injection mode were investigated. Twenty-three wine samples from various origins were analyzed for validation of the procedures. The analytical precision was better than 0.15 per thousand, and no significant isotopic fractionation was observed employing both separative techniques coupled to IRMS. No significant differences and a very strong correlation (r = 0.99) were observed between the 13C/12C ratios obtained by the official method (elemental analyzer/isotope ratio mass spectrometry) and the proposed new methodology. The potential advantages of the developed methods over the traditional one are speed (reducing time required from hours to minutes) and simplicity. In addition, these are the first isotopic methods that allow 13C/12C determination directly from a liquid sample with no previous ethanol isolation, overcoming technical difficulties associated with sample treatment.

  5. Hb A1c Separation by High Performance Liquid Chromatography in Hemoglobinopathies

    Directory of Open Access Journals (Sweden)

    Vani Chandrashekar

    2016-01-01

    Full Text Available Hb A1c measurement is subject to interference by hemoglobin traits and this is dependent on the method used for determination. In this paper we studied the difference between Hb A1c measured by HPLC in hemoglobin traits and normal chromatograms. We also studied the correlation of Hb A1c with age. Hemoglobin analysis was carried out by high performance liquid chromatography. Spearman’s rank correlation was used to study correlation between A1c levels and age. Mann-Whitney U test was used to study the difference in Hb A1c between patients with normal hemoglobin and hemoglobin traits. A total of 431 patients were studied. There was positive correlation with age in patients with normal chromatograms only. No correlation was seen in Hb E trait or beta thalassemia trait. No significant difference in Hb A1c of patients with normal chromatograms and patients with hemoglobin traits was seen. There is no interference by abnormal hemoglobin in the detection of A1c by high performance liquid chromatography. This method cannot be used for detection of A1c in compound heterozygous and homozygous disorders.

  6. Fast and Simple Forensic Red Pen Ink Analysis Using Ultra-Performance Liquid Chromatography (UPLC)

    International Nuclear Information System (INIS)

    Lee, L.C.; Ying, S.L.; Wan Nur Syazwani Wan Mohamad Fuad; Ab Aziz Ishak; Khairul Osman

    2016-01-01

    Ultra-performance liquid chromatography (UPLC) is more effective than high performance liquid chromatography in terms of analysis speed and sensitivity. This paper presents a feasibility study on forensic red pen inks analysis using UPLC. A total of 12 varieties of red ball point pen inks were purchased from selected stationary shop. For each variety, four different individual pens were sampled to provide intra-variability within a particular variety of pen. The proposed approach is very simple that it only involved limited analysis step and chemicals. A total of 144 chromatograms were obtained from red ink entries extracted with 1.5 mL 80 % (v/v) acetonitrile. Peaks originated from pen inks were determined by comparing the chromatograms of both blank paper and blank solvent against that of ink samples. Subsequently, one-way ANOVA was conducted to discriminate all 66 possible pairs for red pen inks. Results showed that the proposed approach giving discriminating power of 95.45 %. The outcome of the study indicates that UPLC could be a fast and simple approach to red ball point pen inks analysis. (author)

  7. A fast isocratic liquid chromatography method for the quantification of xanthophylls and their stereoisomers.

    Science.gov (United States)

    Nimalaratne, Chamila; Lopes-Lutz, Daise; Schieber, Andreas; Wu, Jianping

    2015-12-01

    A fast isocratic liquid chromatography method was developed for the simultaneous quantification of eight xanthophylls (13-Z-lutein, 13'-Z-lutein, 13-Z-zeaxanthin, all-E-lutein, all-E-zeaxanthin, all-E-canthaxanthin, all-E-β-apo-8'-carotenoic acid ethyl ester and all-E-β-apo-8'-carotenal) within 12 min, compared to 90 min by the conventional high-performance liquid chromatography method. The separation was achieved on a YMC C30 reversed-phase column (100 mm x 2.0 mm; 3 μm) operated at 20°C using a methanol/tert-butyl methyl ether/water solvent system at a flow rate of 0.8 mL/min. The method was successfully applied to quantify lutein and zeaxanthin stereoisomers in egg yolk, raw and cooked spinach, and a dietary supplement. The method can be used for the rapid analysis of xanthophyll isomers in different food products and for quality control purposes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Multidimensional spectrometer

    Science.gov (United States)

    Zanni, Martin Thomas; Damrauer, Niels H.

    2010-07-20

    A multidimensional spectrometer for the infrared, visible, and ultraviolet regions of the electromagnetic spectrum, and a method for making multidimensional spectroscopic measurements in the infrared, visible, and ultraviolet regions of the electromagnetic spectrum. The multidimensional spectrometer facilitates measurements of inter- and intra-molecular interactions.

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

    Science.gov (United States)

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

    2016-11-01

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

  10. Rapid determination of some psychotropic drugs in complex matrices by tandem dispersive liquid-liquid microextraction followed by high performance liquid chromatography.

    Science.gov (United States)

    Asghari, Alireza; Fahimi, Ebrahim; Bazregar, Mohammad; Rajabi, Maryam; Boutorabi, Leila

    2017-05-01

    Simple and rapid determinations of some psychotropic drugs in some pharmaceutical wastewater and human plasma samples were successfully accomplished via the tandem dispersive liquid-liquid microextraction combined with high performance liquid chromatography-ultraviolet detection (TDLLME-HPLC-UV). TDLLME of the three psychotropic drugs clozapine, chlorpromazine, and thioridazine was easily performed through two consecutive dispersive liquid-liquid microextractions. By performing this convenient method, proper sample preconcentrations and clean-ups were achieved in just about 7min. In order to achieve the best extraction efficiency, the effective parameters involved were optimized. The optimal experimental conditions consisted of 100μL of CCl 4 (as the extraction organic solvent), and the pH values of 13 and 2 for the donor and acceptor phases, respectively. Under these optimum experimental conditions, the proposed TDLLME-HPLC-UV technique provided a good linearity in the range of 5-3000ngmL -1 for the three psychotropic drugs with the correlation of determinations (R 2 s) higher than 0.996. The limits of quantification (LOQs) and limits of detection (LODs) obtained were 5.0ngmL -1 and 1.0-1.5ngmL -1 , respectively. Also the proper enrichment factors (EFs) of 96, 99, and 88 for clozapine, chlorpromazine, and thioridazine, respectively, and good extraction repeatabilities (relative standard deviations below 9.3%, n=5) were obtained. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Liquid chromatography and ultra-performance liquid chromatography-mass spectrometry fingerprinting of human urine: sample stability under different handling and storage conditions for metabonomics studies.

    Science.gov (United States)

    Gika, Helen G; Theodoridis, Georgios A; Wilson, Ian D

    2008-05-02

    Typically following collection biological samples are kept in a freezer for periods ranging from a few days to several months before analysis. Experience has shown that in LC-MS-based metabonomics research the best analytical practice is to store samples as these are collected, complete the sample set and analyse it in a single run. However, this approach is prudent only if the samples stored in the refrigerator or in the freezer are stable. Another important issue is the stability of the samples following the freeze-thaw process. To investigate these matters urine samples were collected from 6 male volunteers and analysed by LC-MS and ultra-performance liquid chromatography (UPLC)-MS [in both positive and negative electrospray ionization (ESI)] on the day of collection or at intervals of up to 6 months storage at -20 degrees C and -80 degrees C. Other sets of these samples underwent a series of up to nine freeze-thaw cycles. The stability of samples kept at 4 degrees C in an autosampler for up to 6 days was also assessed, with clear differences appearing after 48h. Data was analysed using multivariate statistical analysis (principal component analysis). The results show that sample storage at both -20 and -80 degrees C appeared to ensure sample stability. Similarly up to nine freeze thaw cycles were without any apparent effect on the profile.

  12. Determination of Polycyclic Aromatic Hydrocarbons in Automobile Exhaust by Means of High-Performance Liquid Chromatography with Fluorescence Detection

    DEFF Research Database (Denmark)

    Nielsen, Tom

    1979-01-01

    A chromatographic method has been developed and applied to the determination of polycyclic aromatic hydrocarbons (PAHs) in particulate matter in automobile exhaust, in petrols, and in crankcase oils. The PAHs were purified from other organic compounds by thin-layer chromatography, separated by high......-performance liquid chromatography, and measured by means of on-line fluorescence detection. The identities of the PAHs were verified by comparing the emission spectra obtained by a stop-flow technique with those of standard PAHs...

  13. Rapid Screening and Characterization of Acetylcholinesterase Inhibitors from Yinhuang Oral Liquid Using Ultrafiltration-liquid Chromatography-electrospray Ionization Tandem Mass Spectrometry.

    Science.gov (United States)

    Zhang, Haomin; Guo, Yinan; Meng, Lingwen; Sun, Hui; Yang, Yinping; Gao, Ying; Sun, Jiaming

    2018-01-01

    At present, approximately 17-25 million people in the world suffer from Alzheimer's disease (AD). The most efficacious and acceptable therapeutic drug clinically are the acetylcholinesterase inhibitors (AChEIs). Yinhuang oral liquid is a Chinese medicine preparation which contains AChEIs according to the literatures. However, no strategy has been presented for rapid screening and identification of AChEIs from Yinhuang oral liquid. To develop a method for rapid screening and identification of AChEIs from Yinhuang oral liquid using ultrafiltration-liquid chromatography-electrospray ionization tandem mass spectrometry (UF-LC-ESI-MS/MS). In this study, UF incubation conditions such as enzyme concentration, incubation time, and incubation temperature were optimized so as to get better screening results. The AChEIs from Yinhuang oral liquid were identified by high-performance liquid chromatography-ESI-MS and the improved Ellman method was used for the AChE inhibitory activity test in vitro . The results showed that Yinhuang oral liquid can inhibit the activity of AChE. We screened and identified seven compounds with potential AChE inhibitory activity from Yinhuang oral liquid, which provided experimental basis for the treatment and prevention of AD. The current technique was used to directly screen the active ingredients with acetylcholinesterase inhibition from complex traditional Chinese medicine, which was simple, rapid, accurate, and suitable for high-throughput screening of AChEI from complex systems. A UF-LC-ESI-MS/MS method for rapid screening and identification of AChEIs from Yinhuang oral liquid was developedSeven compounds were screened and identified with potential AChE inhibitory activity from Yinhuang oral liquidIt provided experimental basis of Yinhuang oral liquid for the treating and preventing AD. Abbreviations used: (AD): Alzheimer's disease; (UF-LC-ESI-MS/MS): ultrafiltration-liquid chromatography-electrospray ionization tandem mass spectrometry; (ACh

  14. Determination of tropane alkaloids by heart cutting reversed phase - Strong cation exchange two dimensional liquid chromatography.

    Science.gov (United States)

    Long, Zhen; Zhang, Yanhai; Gamache, Paul; Guo, Zhimou; Steiner, Frank; Du, Nana; Liu, Xiaoda; Jin, Yan; Liu, Xingguo; Liu, Lvye

    2018-01-01

    Current Chinese Pharmacopoeia (ChP) standards apply liquid extraction combined with one dimensional liquid chromatography (1DLC) method for determining alkaloids in herbal medicines. The complex pretreatments lead to a low analytical efficiency and possible component loss. In this study, a heart cutting reversed phase - strong cation exchange two dimensional liquid chromatography (RP - SCX 2DLC) approach was optimized for simultaneously quantifying tropane alkaloids (anisodine, scopolamine and hyoscyamine) in herbal medicines and herbal medicine tablets without further treatment of the filtered extract. The chromatographic conditions were systematically optimized in terms of column type, mobile phase composition and flow rate. To improve peak capacity and obtain symmetric peak shape of alkaloids, a polar group embedded C18 column combined with chaotropic salts was used in the first dimension. To remove the disturbance of non-alkaloids, achieve unique selectivity and acquire symmetric peak shape of alkaloids, an SCX column combined with phosphate buffer was used in the second dimension. Method validation was performed in terms of linearity, precision (0.54-0.82%), recovery (94.1-105.2%), limit of detection (LOD) and limit of quantification (LOQ) of the three analytes varied between 0.067-0.115mgL -1 and 0.195-0.268mgL -1 , respectively. The method demonstrated superiority over 1DLC method in respect of resolution (less alkaloid co-eluted), sample preparation (no pretreatment procedure) and transfer rate (minimum component loss). The optimized RP - SCX 2DLC approach was subsequently applied to quantify target alkaloids in five herbal medicines and herbal medicine tablets from three different manufactures. The results demonstrated that the developed heart cutting RP - SCX 2DLC approach represented a new, strategically significant methodology for the quality evaluation of tropane alkaloid in related herbal medicines that involve complex chemical matrix. Copyright

  15. Analysis of phenolic acids by ionic liquid-in-water microemulsion liquid chromatography coupled with ultraviolet and electrochemical detector.

    Science.gov (United States)

    Peng, Li-Qing; Cao, Jun; Du, Li-Jing; Zhang, Qi-Dong; Shi, Yu-Tin; Xu, Jing-Jing

    2017-05-26

    An environmentally friendly ionic liquid-in-water (IL/W) microemulsion was established and applied as mobile phase in microemulsion liquid chromatography (MELC) with ultraviolet (UV) detection or electrochemical detector (ECD) for analysis of phenolic compounds in real samples. The optimal condition of the method was using the best composition of microemulsion (0.2% w/v [HMIM]PF 6 , 1.0% w/v SDS, 3.0% w/v n-butanol, 95.8% v/v water, pH 2.5) with UV detection. The validation results indicated that the method provided high degree of sensitivity, precision and accuracy with the low limit of detections ranged from 17.9-238ng/mL, satisfactory mean recovery values in the range of 80.1-105% and good linearity (r 2 >0.9994). Additionally, this method exhibited high selectivity and resolution for the analytes and was more eco-friendly compared with traditional MELC method. Consequently, the established IL/W MELC method was successfully applied to simultaneously separate and determine target compounds in Danshen sample and its preparation. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Determination of Levetiracetam in Human Plasma by Dispersive Liquid-Liquid Microextraction Followed by Gas Chromatography-Mass Spectrometry

    Science.gov (United States)

    2016-01-01

    Levetiracetam (LEV) is an antiepileptic drug that is clinically effective in generalized and partial epilepsy syndromes. The use of this drug has been increasing in clinical practice and intra- or -interindividual variability has been exhibited for special population. For this reason, bioanalytical methods are required for drug monitoring in biological matrices. So this work presents a dispersive liquid-liquid microextraction method followed by gas chromatography-mass spectrometry (DLLME-GC-MS) for LEV quantification in human plasma. However, due to the matrix complexity a previous purification step is required. Unlike other pretreatment techniques presented in the literature, for the first time, a procedure employing ultrafiltration tubes Amicon® (10 kDa porous size) without organic solvent consumption was developed. GC-MS analyses were carried out using a linear temperature program, capillary fused silica column, and helium as the carrier gas. DLLME optimized parameters were type and volume of extraction and dispersing solvents, salt addition, and vortex agitation time. Under chosen parameters (extraction solvent: chloroform, 130 μL; dispersing solvent: isopropyl alcohol, 400 μL; no salt addition and no vortex agitation time), the method was completely validated and all parameters were in agreement with the literature recommendations. LEV was quantified in patient's plasma sample using less than 550 μL of organic solvent. PMID:27830105

  17. Versatile ligands for high-performance liquid chromatography: An overview of ionic liquid-functionalized stationary phases.

    Science.gov (United States)

    Zhang, Mingliang; Mallik, Abul K; Takafuji, Makoto; Ihara, Hirotaka; Qiu, Hongdeng

    2015-08-05

    Ionic liquids (ILs), a class of unique substances composed purely by cation and anions, are renowned for their fascinating physical and chemical properties, such as negligible volatility, high dissolution power, high thermal stability, tunable structure and miscibility. They are enjoying ever-growing applications in a great diversity of disciplines. IL-modified silica, transforming the merits of ILs into chromatographic advantages, has endowed the development of high-performance liquid chromatography (HPLC) stationary phase with considerable vitality. In the last decade, IL-functionalized silica stationary phases have evolved into a series of branches to accommodate to different HPLC modes. An up-to-date overview of IL-immobilized stationary phases is presented in this review, and divided into five parts according to application mode, i.e., ion-exchange, normal-phase, reversed-phase, hydrophilic interaction and chiral recognition. Specific attention is channeled to synthetic strategies, chromatographic behavior and separation performance of IL-functionalized silica stationary phases. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. On the use of ionic liquids as mobile phase additives in high-performance liquid chromatography. A review.

    Science.gov (United States)

    García-Alvarez-Coque, M C; Ruiz-Angel, M J; Berthod, A; Carda-Broch, S

    2015-07-09

    The popularity of ionic liquids (ILs) has grown during the last decades in several analytical separation techniques. Consequently, the number of reports devoted to the applications of ILs is still increasing. This review is focused on the use of ILs (mainly imidazolium-based associated to chloride and tetrafluoroborate) as mobile phase additives in high-performance liquid chromatography (HPLC). In this approach, ILs just function as salts, but keep several kinds of intermolecular interactions, which are useful for chromatographic separations. Both cation and anion can be adsorbed on the stationary phase, creating a bilayer. This gives rise to hydrophobic, electrostatic and other specific interactions with the stationary phase and solutes, which modify the retention behaviour and peak shape. This review updates the advances in this field, with emphasis on topics not always deeply considered in the literature, such as the mechanisms of retention, the estimation of the suppressing potency of silanols, modelling and optimisation of the chromatographic performance, and the comparison with other additives traditionally used to avoid the silanol problem. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Determination of thiobencarb in water samples by gas chromatography using a homogeneous liquid-liquid microextraction via flotation assistance procedure

    Directory of Open Access Journals (Sweden)

    H.A. Mashayekhi

    2013-09-01

    Full Text Available Homogeneous liquid-liquid microextraction via flotation assistance (HLLME-FA coupled with gas chromatography-flame ionization detection (GC-FID was applied for the extraction and determination of thiobencarb in water samples. In this study, a special extraction cell was designed to facilitate collection of the low-density solvent extraction. No centrifugation was required in this procedure. The water sample solution was added into the extraction cell which contained an appropriate mixture of toluene (as an extraction solvent and acetone (as a homogeneous solvent. By using air flotation, the organic solvent was collected at the conical part of the designed cell. The effect of the different parameters on the efficiency of extraction such as type and volume of extraction and homogeneous solvents, ionic strength and extraction time were studied and optimized. Under the optimal conditions, linearity of the method was in the range of 1.0-200 µg L-1. The relative standard deviations in the real samples varied from 7.8-11.7 % (n = 3. The proposed method was successfully applied to analysis of thiobencarb in the water samples and satisfactory results were obtained.DOI: http://dx.doi.org/10.4314/bcse.v27i3.4

  20. Determination of Levetiracetam in Human Plasma by Dispersive Liquid-Liquid Microextraction Followed by Gas Chromatography-Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Greyce Kelly Steinhorst Alcantara

    2016-01-01

    Full Text Available Levetiracetam (LEV is an antiepileptic drug that is clinically effective in generalized and partial epilepsy syndromes. The use of this drug has been increasing in clinical practice and intra- or -interindividual variability has been exhibited for special population. For this reason, bioanalytical methods are required for drug monitoring in biological matrices. So this work presents a dispersive liquid-liquid microextraction method followed by gas chromatography-mass spectrometry (DLLME-GC-MS for LEV quantification in human plasma. However, due to the matrix complexity a previous purification step is required. Unlike other pretreatment techniques presented in the literature, for the first time, a procedure employing ultrafiltration tubes Amicon® (10 kDa porous size without organic solvent consumption was developed. GC-MS analyses were carried out using a linear temperature program, capillary fused silica column, and helium as the carrier gas. DLLME optimized parameters were type and volume of extraction and dispersing solvents, salt addition, and vortex agitation time. Under chosen parameters (extraction solvent: chloroform, 130 μL; dispersing solvent: isopropyl alcohol, 400 μL; no salt addition and no vortex agitation time, the method was completely validated and all parameters were in agreement with the literature recommendations. LEV was quantified in patient’s plasma sample using less than 550 μL of organic solvent.

  1. Automated high performance liquid chromatography and liquid scintillation counting determination of pesticide mixture octanol/water partition rates

    International Nuclear Information System (INIS)

    Moody, R.P.; Carroll, J.M.; Kresta, A.M.

    1987-01-01

    Two novel methods are reported for measuring octanol/water partition rates of pesticides. A liquid scintillation counting (LSC) method was developed for automated monitoring of 14 C-labeled pesticides partitioning in biphasic water/octanol cocktail systems with limited success. A high performance liquid chromatography (HPLC) method was developed for automated partition rate monitoring of several constituents in a pesticide mixture, simultaneously. The mean log Kow +/- SD determined from triplicate experimental runs were for: 2,4-D-DMA (2,4-dichlorophenoxyacetic acid dimethylamine), 0.65 +/- .17; Deet (N,N-diethyl-m-toluamide), 2.02 +/- .01; Guthion (O,O-dimethyl-S-(4-oxo-1,2,3-benzotriazin-3(4H)-ylmethyl) phosphorodithioate), 2.43 +/- .03; Methyl-Parathion (O,O-dimethyl-O-(p-nitrophenyl) phosphorothioate), 2.68 +/- .05; and Fenitrothion (O,O-dimethyl O-(4-nitro-m-tolyl) phosphorothioate), 3.16 +/- .03. A strong positive linear correlation (r = .9979) was obtained between log Kow and log k' (log Kow = 2.35 (log k') + 0.63). The advantages that this automated procedure has in comparison with the standard manual shake-flask procedure are discussed

  2. Separation of tungsten from molybdenum by liquid-liquid extraction and extraction chromatography using thiocyanate and a quarternary ammonium salt

    International Nuclear Information System (INIS)

    Yonezawa, C.; Onishi, H.

    1977-01-01

    Methods were developed for the separation of tungsten from molybdenum by liquid-liquid extraction and extraction chromatography using thiocyanate and a quaternary ammonium salt, Zephiramine. Tungsten was extracted into chloroform as an ion associate of tungsten(V)-thiocyanate complex and Zephiramine cation was retained on a column of Teflon powder coated with Zephiramine, but molybdenum(III) was neither extracted nor retained. The extraction chromatographic method was succesfully applied to the determination of trace amounts of tungsten in molybdenum by neutron activation analysis. The γ-ray spectrum, observed with the Ge(Li) detector, of tungsten fraction separated from irradiated molybdenum are shown. The peaks of 99 Mo, sup(99m)Tc, and sup(99m)Nb (produced by 92 Mo(n,p)sup(99m)Nb) were seen, but these nuclides did nit interfere with the determination of tungsten using a NaI(Tl) detector. The results of the neutron activation analysis of a sample of ammonium molybdate agreed quite well with that of the spectrophotometric determination after extraction chromatographic separation. (T.G.)

  3. High-performance liquid chromatography separation of unsaturated organic compounds by a monolithic silica column embedded with silver nanoparticles.

    Science.gov (United States)

    Zhu, Yang; Morisato, Kei; Hasegawa, George; Moitra, Nirmalya; Kiyomura, Tsutomu; Kurata, Hiroki; Kanamori, Kazuyoshi; Nakanishi, Kazuki

    2015-08-01

    The optimization of a porous structure to ensure good separation performances is always a significant issue in high-performance liquid chromatography column design. Recently we reported the homogeneous embedment of Ag nanoparticles in periodic mesoporous silica monolith and the application of such Ag nanoparticles embedded silica monolith for the high-performance liquid chromatography separation of polyaromatic hydrocarbons. However, the separation performance remains to be improved and the retention mechanism as compared with the Ag ion high-performance liquid chromatography technique still needs to be clarified. In this research, Ag nanoparticles were introduced into a macro/mesoporous silica monolith with optimized pore parameters for high-performance liquid chromatography separations. Baseline separation of benzene, naphthalene, anthracene, and pyrene was achieved with the theoretical plate number for analyte naphthalene as 36,000 m(-1). Its separation function was further extended to cis/trans isomers of aromatic compounds where cis/trans stilbenes were chosen as a benchmark. Good separation of cis/trans-stilbene with separation factor as 7 and theoretical plate number as 76,000 m(-1) for cis-stilbene was obtained. The trans isomer, however, is retained more strongly, which contradicts the long- established retention rule of Ag ion chromatography. Such behavior of Ag nanoparticles embedded in a silica column can be attributed to the differences in the molecular geometric configuration of cis/trans stilbenes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Development of a high performance liquid chromatography method and a liquid chromatography-tandem mass spectrometry method with pressurized liquid extraction for simultaneous quantification and confirmation of cyromazine, melamine and its metabolites in foods of animal origin

    International Nuclear Information System (INIS)

    Yu Huan; Tao Yanfei; Chen Dongmei; Wang Yulian; Liu Zhaoying; Pan Yuanhu; Huang Lingli; Peng Dapeng; Dai Menghong; Liu Zhenli; Yuan Zonghui

    2010-01-01

    Simple and sensitive methods have been developed for simultaneous detection of cyromazine, melamine and their metabolites (ammeline, ammelide and cyanuric acid) in samples of animal origins. These include a high performance liquid chromatography (HPLC) method and a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method and are useful in regular monitoring and in toxicity studies of these molecules. Representative samples used in this study include muscles and livers of swine, bovine, sheep and chicken, kidneys of swine, bovine and sheep, and milk powder. A new sample preparation procedure with pressurized liquid extraction (PLE) at 1400 psi and 70 deg. C was investigated. Quantification of these five compounds by HPLC was achieved using an APS-2 column with UV detection at 230 nm. Limit of detection (LOD) was at 10 μg kg -1 , and limit of quantification (LOQ) was at 40 μg kg -1 . Recoveries of the five analytes in spiked samples ranged from 72.2% to 115.4% with RSD less than 12%. Confirmatory analysis of the analytes was performed using LC-MS/MS in selected reaction monitoring (SRM) mode. The LOD and LOQ were 5 μg kg -1 and 15 μg kg -1 , respectively. This is the first simultaneous analysis of cyromazine, melamine, ammeline, ammelide and cyanuric acid residues in complex tissue samples using PLE and HPLC. It is expected that these methods will find many practical applications in evaluating the safety of cyromazine, melamine and their metabolites.

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

    Science.gov (United States)

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

  6. Application of dispersive liquid-liquid microextraction for the preconcentration of eight parabens in real samples and their determination by high-performance liquid chromatography.

    Science.gov (United States)

    Shen, Xiong; Liang, Jian; Zheng, Luxia; Lv, Qianzhou; Wang, Hong

    2017-11-01

    A simple and sensitive method for the simultaneous determination of eight parabens in human plasma and urine samples was developed. The samples were preconcentrated using dispersive liquid-liquid microextraction based on the solidification of floating organic drops and determined by high-performance liquid chromatography with ultraviolet detection. The influence of variables affecting the extraction efficiency was investigated and optimized using Placket-Burman design and Box-Behnken design. The optimized values were: 58 μL of 1-decanol (as extraction solvent), 0.65 mL methanol (as disperser solvent), 1.5% w/v NaCl in 5.0 mL of sample solution, pH 10.6, and 4.0 min centrifugation at 4000 rpm. The extract was injected into the high-performance liquid chromatography system for analysis. Under the optimum conditions, the linear ranges for eight parabens in plasma and urine were 1.0-1000 ng/mL, with correlation coefficients above 0.994. The limit of detection was 0.2-0.4 and 0.1-0.4 ng/mL for plasma and urine samples, respectively. Relative recoveries were between 80.3 and 110.7%, while relative standard deviations were less than 5.4%. Finally, the method was applied to analyze the parabens in 98 patients of primary breast cancer. Results showed that parabens existed widely, at least one paraben detected in 96.9% (95/98) of plasma samples and 98.0% (96/98) of urine samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. The gas–liquid chromatography of carboxylic acid esters of the urinary 11-deoxy-17-oxo steroids

    Science.gov (United States)

    Sadler, Patricia A.; Kellie, A. E.

    1967-01-01

    1. The gas–liquid-chromatographic separations of the acetate, propionate, n-butyrate, isobutyrate and n-valerate esters of androsterone, aetiocholanolone and dehydroepiandrosterone were studied on a 1% neopentyl glycol sebacate column. The n-butyrate, isobutyrate and n-valerate esters were well resolved. 2. The three steroids derived from hydrolysed urinary 17-oxo steroid conjugate extracts were analysed by gas–liquid chromatography after conversion into their n-butyrate esters. The results were compared with independent determinations involving chromatography on alumina. PMID:4227802

  8. Community air monitoring for pesticides-part 2: multiresidue determination of pesticides in air by gas chromatography, gas chromatography-mass spectrometry, and liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Hengel, Matt; Lee, P

    2014-03-01

    Two multiresidue methods were developed to determine pesticides in air collected in California. Pesticides were trapped using XAD-4 resin and extracted with ethyl acetate. Based on an analytical method from the University of California Davis Trace Analytical Laboratory, pesticides were detected by analyzing the extract by gas chromatography-mass spectrometry (GC-MS) to determine chlorothalonil, chlorthal-dimethyl, cycloate, dicloran, dicofol, EPTC, ethalfluralin, iprodione, mefenoxam, metolachlor, PCNB, permethrin, pronamide, simazine, trifluralin, and vinclozolin. A GC with a flame photometric detector was used to determine chlorpyrifos, chlorpyrifos oxon, diazinon, diazinon oxon, dimethoate, dimethoate oxon, fonophos, fonophos oxon, malathion, malathion oxon, naled, and oxydemeton. Trapping efficiencies ranged from 78 to 92 % for low level (0.5 μg) and 37-104 % for high level (50 and 100 μg) recoveries. Little to no degradation of compounds occurred over 31 days; recoveries ranged from 78 to 113 %. In the California Department of Food and Agriculture (CDFA) method, pesticides were detected by analyzing the extract by GC-MS to determine chlorothalonil, chlorpyrifos, cypermethrin, dichlorvos, dicofol, endosulfan 1, endosulfan sulfate, oxyfluorfen, permethrin, propargite, and trifluralin. A liquid chromatograph coupled to a MS was used to determine azinphos-methyl, chloropyrifos oxon, DEF, diazinon, diazinon oxon, dimethoate, dimethoate oxon, diuron, EPTC, malathion, malathion oxon, metolachlor, molinate, norflurazon, oryzalin, phosmet, propanil, simazine and thiobencarb. Trapping efficiencies for compounds determined by the CDFA method ranged from 10 to 113, 22 to 114, and 56 to 132 % for 10, 5, and 2 μg spikes, respectively. Storage tests yielded 70-170 % recovery for up to 28 days. These multiresidue methods represent flexible, sensitive, accurate, and cost-effective ways to determine residues of various pesticides in ambient air.

  9. Sensitive liquid chromatography-tandem mass spectrometry method for quantification of hydrochlorothiazide in human plasma.

    Science.gov (United States)

    Ramakrishna, N V S; Vishwottam, K N; Manoj, S; Koteshwara, M; Wishu, S; Varma, D P

    2005-12-01

    A simple, rapid, sensitive and specific liquid chromatography-tandem mass spectrometry method was developed and validated for quantification of hydrochlorothiazide (I), a common diuretic and anti-hypertensive agent. The analyte and internal standard, tamsulosin (II) were extracted by liquid-liquid extraction with diethyl ether-dichloromethane (70:30, v/v) using a Glas-Col Multi-Pulse Vortexer. The chromatographic separation was performed on a reversed-phase column (Waters symmetry C18) with a mobile phase of 10 mm ammonium acetate-methanol (15:85, v/v). The protonated analyte was quantitated in negative ionization by multiple reaction monitoring with a mass spectrometer. The mass transitions m/z 296.1 solidus in circle 205.0 and m/z 407.2 solidus in circle 184.9 were used to measure I and II, respectively. The assay exhibited a linear dynamic range of 0.5-200 ng/mL for hydrochlorothiazide in human plasma. The lower limit of quantitation was 500 pg/mL, with a relative standard deviation of less than 9%. Acceptable precision and accuracy were obtained for concentrations over the standard curve ranges. A run time of 2.5 min for each sample made it possible to analyze a throughput of more than 400 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic, bioavailability or bioequivalence studies. (c) 2005 John Wiley & Sons, Ltd.

  10. On-line radiometry in high-performance liquid chromatography using a storage loop

    International Nuclear Information System (INIS)

    Nieuwkerk, H.J. van.

    1987-01-01

    Difficulty with radiometric chromatography is that large measured volumes are required for accurate detections, but large volumes cause band widening and thus poor separation capacity. The solution proposed here is based on the use of a capillary storage loop for temporary residence of the column eluate. To avoid back mixing, the liquid is interspaced with a second, immiscible, phase ('spacer') so as to form a sequence of small 10-50 μl separate segments. This train passes the on-line radiometric detector to obtain a first scan of the chromatogram, called the 'direct' measurement. It then reaches the storage loop. The usual on-line UV measurement is done in the same run. The eluate cum spacer is, at a later stage, pumped through the detector at a greatly reduced flow rate to obtain the 'reversed' or 'delayed' measurement. Beta-detection is based on liquid scintillation. Accordingly, the (organic) liquid scintillant is used as the 'spacer'. In most cases it is possible to extract the analyte from the aqueous eluate into the organic phase during transport to and storage in the loop. This ensures a high counting efficiency. If the analyte is non-extractable, the counting efficiency is considerably less but the number of counts collected is still sufficient for quantitative assay, due to the extended counting time. The report is divided into 5 chapters, each dealing with a radiometric HPCL separation making use of this method. 36 figs.; 124 refs.; 16 tables

  11. [Determination of amitrole in agricultural products by high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Li, Li; Fu, Jian; Gao, Hongliang; Ren, Haitao; Lou, Xishan; Guan, Lihui

    2010-03-01

    A high performance liquid chromatography-tandem mass spectrometry method (HPLC-MS/MS) was developed for the analysis of amitrole residues in agricultural products. The samples were extracted by 25% acetone for wheat, fish, pork and liver samples, 1% acetic acid-25% acetone for maize and peanut samples, 1% acetic acid solution for honeysuckle, the powder of ginger, the powder of bunge prickly ash and tea leaves samples, 1% acetic acid solution-dichloromethane for apple, pineapple, spinach, carrot, perilla leaves samples, respectively, followed by liquid-liquid extraction with dichloromethane. The samples were then cleaned up by PCX or Envi-Carb solid-phase extraction cartridge. The amitrole was determined and confirmed by HPLC-MS/MS. The results showed a linear relationship in the range of 0.005 -0.1 mg/kg for amitrole. The correlation coefficient was 0.999 7. The average recoveries of amitrole in wheat, maize, peanut, pineapple, apple, carrot, spinach, pork, the powder of ginger, the powder of bunge prickly ash, perilla, liver, fish, honeysuckle and tea were 67.5% - 98.1%. The relative standard deviations (RSDs) were 1.0% - 9.8%. The limits of quantitation were 10 microg/kg for wheat, maize, peanut, pineapple, apple, carrot, spinach, pork, perilla, liver, fish, honeysuckle and 20 microg/kg for the powder of bunge prickly ash, the powder of ginger and tea, respectively. The method is simple, sensitive and accurate.

  12. Determination of parabens using two microextraction methods coupled with capillary liquid chromatography-UV detection.

    Science.gov (United States)

    Chen, Chen-Wen; Hsu, Wen-Chan; Lu, Ya-Chen; Weng, Jing-Ru; Feng, Chia-Hsien

    2018-02-15

    Parabens are common preservatives and environmental hormones. As such, possible detrimental health effects could be amplified through their widespread use in foods, cosmetics, and pharmaceutical products. Thus, the determination of parabens in such products is of particular importance. This study explored vortex-assisted dispersive liquid-liquid microextraction techniques based on the solidification of a floating organic drop (VA-DLLME-SFO) and salt-assisted cloud point extraction (SA-CPE) for paraben extraction. Microanalysis was performed using a capillary liquid chromatography-ultraviolet detection system. These techniques were modified successfully to determine four parabens in 19 commercial products. The regression equations of these parabens exhibited good linearity (r 2 =0.998, 0.1-10μg/mL), good precision (RSD<5%) and accuracy (RE<5%), reduced reagent consumption and reaction times (<6min), and excellent sample versatility. VA-DLLME-SFO was also particularly convenient due to the use of a solidified extract. Thus, the VA-DLLME-SFO technique was better suited to the extraction of parabens from complex matrices. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Ultra-sensitive high performance liquid chromatography-laser-induced fluorescence based proteomics for clinical applications.

    Science.gov (United States)

    Patil, Ajeetkumar; Bhat, Sujatha; Pai, Keerthilatha M; Rai, Lavanya; Kartha, V B; Chidangil, Santhosh

    2015-09-08

    An ultra-sensitive high performance liquid chromatography-laser induced fluorescence (HPLC-LIF) based technique has been developed by our group at Manipal, for screening, early detection, and staging for various cancers, using protein profiling of clinical samples like, body fluids, cellular specimens, and biopsy-tissue. More than 300 protein profiles of different clinical samples (serum, saliva, cellular samples and tissue homogenates) from volunteers (normal, and different pre-malignant/malignant conditions) were recorded using this set-up. The protein profiles were analyzed using principal component analysis (PCA) to achieve objective detection and classification of malignant, premalignant and healthy conditions with high sensitivity and specificity. The HPLC-LIF protein profiling combined with PCA, as a routine method for screening, diagnosis, and staging of cervical cancer and oral cancer, is discussed in this paper. In recent years, proteomics techniques have advanced tremendously in life sciences and medical sciences for the detection and identification of proteins in body fluids, tissue homogenates and cellular samples to understand biochemical mechanisms leading to different diseases. Some of the methods include techniques like high performance liquid chromatography, 2D-gel electrophoresis, MALDI-TOF-MS, SELDI-TOF-MS, CE-MS and LC-MS techniques. We have developed an ultra-sensitive high performance liquid chromatography-laser induced fluorescence (HPLC-LIF) based technique, for screening, early detection, and staging for various cancers, using protein profiling of clinical samples like, body fluids, cellular specimens, and biopsy-tissue. More than 300 protein profiles of different clinical samples (serum, saliva, cellular samples and tissue homogenates) from healthy and volunteers with different malignant conditions were recorded by using this set-up. The protein profile data were analyzed using principal component analysis (PCA) for objective

  14. Determination of Bisphenol A and Bisphenol AF in Vinegar samples by two-component mixed ionic liquid dispersive liquid-phase microextraction coupled with high performance liquid chromatography

    International Nuclear Information System (INIS)

    Tai, Z.; Liu, M.; Hu, X.; Yang, Y.

    2014-01-01

    This paper describes a sensitive and simple method for the determination of bisphenol A (BPA) and bisphenol AF (BPAF) in vinegar samples using two-component mixed ionic liquid dispersive liquid-phase microextraction coupled with high performance liquid chromatography. In this work, BPA and BPAF were selected as the model analytes, and two-component mixed ionic liquid included 1-butyl-3-methylimidazolium hexafluorophosphate ((C4Mim)PF6) and 1-hexyl-3-methyl-imidazolium hexafluorophosphate ((C6Mim)PF6) was used as the extraction solvent for the first time here. Parameters that affect the extraction efficiency were investigated. Under the optimum conditions, good linear relationships were discovered in the range of 1.0-100 micro g/L for BPA and 2.0-150 micro g/L for BPAF, respectively. Detection limits of proposed method based on the signal-to-noise ratio (S/N=3) were in the range of 0.15-0.38 micro g/L. The efficiencies of proposed method have also been demonstrated with spiked real vinegar samples. The result show this method/ procedure to be a more efficient approach for the determination of BPA and BPAF in real vinegar, presenting average recovery rate of 89.3-112 % and precision values of 0.9-13.5% (RSDs, n = 6). In comparison with traditional solid phase extraction procedures this method results in lower solvent consumption, low pollution levels, and faster sample preparation. (author)

  15. Determination of Gemfibrozil (Lipitor and Lopid in Water, Biological Fluids and Drug Matrix by Dispersive Liquid-Liquid micro Extraction (DLLME and Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Ghorbani A.

    2014-07-01

    Full Text Available In this study Dispersive liquid-liquid micro extraction (DLLME coupled with High performance liquid chromatography was applied for the determination of Gemfibrozil in water, drug`s matrix and biological liquids (human plasma and urine. In this method, the appropriate mixture of extraction solvent (200 μl chlorophorm and disperser solvent (1 ml methanol are injected rapidly into the aqueous sample (10.0 ml by syringe, cloudy solution is formed that consisted of fine particles of extraction solvent which is dispersed entirely into aqueous phase. The mixture was centrifuged and the extraction solvent is sedimented on the bottom of the conical test tube. 50 μl of the sedimented phase is puted in a vial and it`s solvent is evaporated. Then 1ml methanol injected to vial and 20 μL of it injected into the HPLC for separation and determination of Gemfibrozil. Some important parameters, such as kind of extraction and disperser solvent, volume of them, extraction time, pH and ionic strength of the aqueous feed solution were optimized. Under the optimum conditions, the enrichment factors and extraction recoveries were 10 and 93.64%. The linear range was (0.1-100.0 mgl-1, limit of detection was 12.3 mgl-1. The relative standard deviations (RSD for 2 mgl-1 of Gemfibrozil in water were 1.3%, (n=10.

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

    Science.gov (United States)

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

    2017-10-15

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

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

    OpenAIRE

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

    2013-01-01

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

  18. On-line hyphenation of centrifugal partition chromatography and high pressure liquid chromatography for the fractionation of flavonoids from Hippophaë rhamnoides L. berries.

    Science.gov (United States)

    Michel, Thomas; Destandau, Emilie; Elfakir, Claire

    2011-09-09

    Centrifugal Partition Chromatography (CPC), a liquid-liquid preparative chromatography using two immiscible solvent systems, benefits from numerous advantages for the separation or purification of synthetic or natural products. This study presents the on-line hyphenation of CPC-Evaporative Light Scattering Detector (CPC-ELSD) with High Performance Liquid Chromatography-UV (HPLC-UV) for the fractionation of flavonols from a solvent-free microwave extract of sea buckthorn (Hippophaë rhamnoides L., Elaeagnaceae) berries. An Arizona G system was used for the fractionation of flavonoids by CPC and a fused core Halo C18 column allowed the on-line analyses of collected fractions by HPLC. The on-line CPC/HPLC procedure allowed the simultaneous fractionation step at preparative scale combined with the HPLC analyses which provide direct fingerprint of collected fractions. Thus the crude extract was simplified and immediate information on the composition of fractions could be obtained. Furthermore, this methodology reduced the time of post-fractionation steps and facilitated identification of main molecules by Mass Spectrometry (MS). Rutin, isorhamnetin-3-O-rutinoside, isorhamnetin-3-O-glucoside, quercetin-3-O-glucoside, isorhamnetin-rhamnoside, quercetin and isorhamnetin were identified. CPC-ELSD/HPLC-UV could be considered as a high-throughput technique for the guided fractionation of bioactive natural products from complex crude extracts. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. Transverse Position Reconstruction in a Liquid Argon Time Projection Chamber using Principal Component Analysis and Multi-Dimensional Fitting

    Science.gov (United States)

    Watson, Andrew William

    2017-08-01

    pocket above the liquid region, respectively. One of the lingering challenges in this experiment, however, is the determination of an event's position along the other two spatial dimensions, that is, its transverse or "xy" position. Some liquid noble element TPCs have achieved remarkably accurate event position reconstructions, typically using the relative amounts of S2 light collected by Photo-Multiplier Tubes ("PMTs") as the input data to their reconstruction algorithms. This approach has been partic- ularly challenging in DarkSide-50, partly due to unexpected asymmetries in the detector, and partly due to the design of the detector itself. A variety of xy-Reconstruction methods ("xy methods" for short) have come and gone in DS- 50, with only a few of them providing useful results. The xy method described in this dissertation is a two-step Principal Component Analysis / Multi-Dimensional Fit (PCAMDF) reconstruction. In a nutshell, this method develops a functional mapping from the 19-dimensional space of the signal received by the PMTs at the "top" (or the "anode" end) of the DarkSide-50 TPC to each of the transverse coordinates, x and y. PCAMDF is a low-level "machine learning" algorithm, and as such, needs to be "trained" with a sample of representative events; in this case, these are provided by the DarkSide geant4-based Monte Carlo, g4ds. In this work, a thorough description of the PCAMDF xy-Reconstruction method is provided along with an analysis of its performance on MC events and data. The method is applied to several classes of data events, including coincident decays, external gamma rays from calibration sources, and both atmospheric argon "AAr" and underground argon "UAr". Discrepancies between the MC and data are explored, and fiducial volume cuts are calculated. Finally, a novel method is proposed for finding the accuracy of the PCAMDF reconstruction on data by using the asymmetry of the S2 light collected on the anode and cathode PMT arrays as a function

  20. Improvement of mineral oil saturated and aromatic hydrocarbons determination in edible oil by liquid-liquid-gas chromatography with dual detection.

    Science.gov (United States)

    Zoccali, Mariosimone; Barp, Laura; Beccaria, Marco; Sciarrone, Danilo; Purcaro, Giorgia; Mondello, Luigi

    2016-02-01

    Mineral oils, which are mainly composed of saturated hydrocarbons and aromatic hydrocarbons, are widespread food contaminants. Liquid chromatography coupled to gas chromatography with flame ionization detection represents the method of choice to determine these two families. However, despite the high selectivity of this technique, the presence of olefins (particularly squalene and its isomers) in some samples as in olive oils, does not allow the correct quantification of the mineral oil aromatic hydrocarbons fraction, requiring additional off-line tools to eliminate them. In the present research, a novel on-line liquid chromatography coupled to gas chromatography method is described for the determination of hydrocarbon contamination in edible oils. Two different liquid chromatography columns, namely a silica one (to retain the bulk of the matrix) and a silver-ion one (which better retains the olefins), were coupled in series to obtain the mineral oil aromatic hydrocarbons hump free of interfering peaks. Furthermore, the use of a simultaneous dual detection, flame ionization detector and triple quadrupole mass spectrometer allowed us not only to quantify the mineral oil contamination, but also to evaluate the presence of specific markers (i.e. hopanes) to confirm the petrogenic origin of the contamination. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Simultaneous separation of antihyperlipidemic drugs by green ultrahigh-performance liquid chromatography-diode array detector method: Improving the health of liquid chromatography.

    Science.gov (United States)

    Alghazi, Mansoor; Alanazi, Fars; Mohsin, Kazi; Siddiqui, Nasir Ali; Shakeel, Faiyaz; Haq, Nazrul

    2017-04-01

    Statins in combination with fibrates show beneficial effects on the lipoprotein profile of patients because they have positive complimentary effects on lipid profile. A new green ultrahigh-performance liquid chromatography-diode array detector method for simultaneous analysis of simvastatin (SMV) and fenofibrate (FNF) in standard form, marketed formulations, and self-emulsifying drug delivery system formulations was developed and validated in the present investigation. The method utilized C 18 as stationary phase and a combination of methanol:water (8:2) as an eluent. It was found that selected eluent provided short run time (2.5 minutes), better peak symmetry and satisfactory values of other chromatographic parameters such as resolution (Rs=2.325), capacity factor (k, 3.0 and 4.2 for SMV and FNF, respectively), selectivity (α =1.4), and number of theoretical plates (N, 4265 and 5285 for SMV and FNF, respectively). An excellent linear relationship (r 2 0.998 and 0.997 for SMV and FNF, respectively) was observed for linear regression data for the calibration plots. The developed system was validated for accuracy, precision, robustness (˃ 2% for both drugs) and recovery (98-102% for both drugs). Results obtained from the statistical treatment of the values obtained for different parameters proved that the method is suitable, reproducible, and selective for the simultaneous analysis of SMV and FNF in bulk, marketed, and self-emulsifying drug delivery system formulations. The replacement of commonly applied toxic solvents with innocuous and environmentally benign solvents provides a better option than the more toxic processes in drug analysis. Copyright © 2016. Published by Elsevier B.V.

  2. Improved separation of conjugated fatty acid methyl esters by silver ion-high-performance liquid chromatography.

    Science.gov (United States)

    Sehat, N; Rickert, R; Mossoba, M M; Kramer, J K; Yurawecz, M P; Roach, J A; Adlof, R O; Morehouse, K M; Fritsche, J; Eulitz, K D; Steinhart, H; Ku, Y

    1999-04-01

    Operating from one to six silver ion-high-performance liquid chromatography (Ag+-HPLC) columns in series progressively improved the resolution of the methyl esters of conjugated linoleic acid (CLA) isomeric mixtures from natural and commercial products. In natural products, the 8 trans, 10 cis-octadecadienoic (18:2) acid was resolved from the more abundant 7 trans, 9 cis-18:2, and the 10 trans, 12 cis-18:2 was separated from the major 9 cis, 11 trans-18:2 peak. In addition, both 11 trans, 13 cis-18:2 and 11 cis, 13 trans-18:2 isomers were found in natural products and were separated; the presence of the latter, 11 cis, 13 trans-18:2, was established in commercial CLA preparations. Three Ag+-HPLC columns in series appeared to be the best compromise to obtain satisfactory resolution of most CLA isomers found in natural products. A single Ag+-HPLC column in series with one of several normal-phase columns did not improve the resolution of CLA isomers as compared to that of the former alone. The 20:2 conjugated fatty acid isomers 11 cis, 13 trans-20:2 and 12 trans, 14 cis-20:2, which were synthesized by alkali isomerization from 11 cis, 14 cis-20:2, eluted in the same region of the Ag+-HPLC chromatogram just before the corresponding geometric CLA isomers. Therefore, CLA isomers will require isolation based on chain length prior to Ag+-HPLC separation. The positions of conjugated double bonds in 20:2 and 18:2 isomers were established by gas chromatography-electron ionization mass spectrometry as their 4,4-dimethyloxazoline derivatives. The double-bond geometry was determined by gas chromatography-direct deposition-Fourier transform infrared spectroscopy and by the Ag+-HPLC relative elution order.

  3. Microcolumn high pressure liquid chromatography with a glass-frit nebulizer interface for plasma emission detection

    International Nuclear Information System (INIS)

    Ibrahim, M.; Nisamaneepong, W.; Caruso, J.

    1985-01-01

    Microcolumn high pressure liquid chromatography (micro-HPLC) is rapidly gaining recognition as a practical separation tool for organometallic compounds. The use of the inductively coupled plasma (ICP) as a detector for micro-HPLC is studied. Several miniaturized glass-frit nebulizers are investigated as interfaces between the output of the microbore column and the ICP torch. Their performance with aqueous and methanolic solutions is evaluated by direct nebulization and flow injection analysis. The most efficient of these nebulizers is used in the micro-HPLC/ICP study of some Cd, Pb, and Zn organometallic compounds. Detection limits of 1.92 ng of Pb for tetramethyllead and 5.01 ng of Pb for tetraethyllead are obtained and compared with regular HPLC/ICP of these same compounds. Approximately equivalent detection limits were obtained when using a microwave induced plasma as an alternate plasma source

  4. Uncovering biologically significant lipid isomers with liquid chromatography, ion mobility spectrometry and mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Kyle, Jennifer E.; Zhang, Xing; Weitz, Karl K.; Monroe, Matthew E.; Ibrahim, Yehia M.; Moore, Ronald J.; Cha, Jeeyeon; Sun, Xiaofei; Lovelace, Erica S.; Wagoner, Jessica; Polyak, Steve; Metz, Thomas O.; Dey, Sudhansu K.; Smith, Richard D.; Burnum-Johnson, Kristin E.; Baker, Erin Shammel

    2016-01-01

    Understanding how biological molecules are generated, metabolized and eliminated in living systems is important for interpreting processes such as immune response and disease pathology. While genomic and proteomic studies have provided vast amounts of information over the last several decades, interest in lipidomics has also grown due to improved analytical technologies revealing altered lipid metabolism in type 2 diabetes, cancer, and lipid storage disease. Liquid chromatography and mass spectrometry (LC-MS) measurements are currently the dominant approach for characterizing the lipidome by providing detailed information on the spatial and temporal composition of lipids. However, interpreting lipids’ biological roles is challenging due to the existence of numerous structural and stereoisomers (i.e. distinct acyl chain and double-bond positions), which are unresolvable using present LC-MS approaches. Here we show that combining structurally-based ion mobility spectrometry (IMS) with LC-MS measurements distinguishes lipid isomers and allows insight into biological and disease processes.

  5. High-performance liquid chromatography of metal complexes of pheophytins a and b

    International Nuclear Information System (INIS)

    Brykina, G.D.; Lazareva, E.E.; Uvarova, M.I.; Shpigun, O.A.

    1997-01-01

    Cu(2), Zn(2), Pb(2), Hg(2), and Ce(4) complexes of phenophytins a and b were synthesized. The chromatographic retention parameters of pheophytins a and b, chlorophylls a and b, and the above complexes were determined under conditions of normal-phase and reversed-phase high-performance liquid chromatography (HPLC). The adsorption of metal pheophytinates in the hexane-n-butanol (96:4)-Silasorb 600 and acetonitrile-ethanol-acetic acid (40:40:16)-Nucleosil C 18 systems was studied by HPLC. Factors that affect the chromatographic and adsorption characteristics of compounds (structural differences between pheophytinates of the a and b series, the nature of the central metal atom, and the nature of the mobile and stationary phases) are discussed. It is demonstrated that pheophytins a and b their metal complexes can be identified and quantiatively determined by HPLC in the concentration range (0.6-44.0)[10 -6 M

  6. Multielement determination of rare earth elements by liquid chromatography/inductively coupled plasma atomic emission spectrometry

    International Nuclear Information System (INIS)

    Sawatari, Hideyuki; Asano, Takaaki; Hu, Xincheng; Saizuka, Tomoo; Itoh, Akihide; Hirose, Akio; Haraguchi, Hiroki

    1995-01-01

    The rapid determination of rare earth elements (REEs) has been investigated by an on-line system of high performance liquid chromatography/multichannel inductively coupled plasma atomic emission spectrometry. In the present system, all REEs could be detected simultaneously in a single chromatographic measurement without spectral interferences. Utilizing a cation exchange column and 2-hydroxy-2-methylpropanoic acid aqueous solution as the mobile phase, the detection limits of 0.4-30 ng ml -1 for all REEs were obtained. The system was applied to the determination of REEs in geological standard rock samples and rare earth impurities in high purity rare earth oxides. The REEs in standard rocks could be determined by the present HPLC/ICP-AES system without pretreatment after acid digestion, although the detection limits were not sufficient for the analysis of rare earth oxides. (author)

  7. Determination of Ivermectin in Medicated Feeds by Liquid Chromatography with Fluorescence Detection

    Science.gov (United States)

    2013-01-01

    A labour- and time-effective analytical procedure for determination of ivermectin in medicated feed at recommended level of 2.0 mg kg−1 has been developed and validated. The analyte was extracted from grinded feed samples with acetonitrile and derivatisated with N-methylimidazole and trifluoracetic anhydride. The fluorescent derivatives were analysed by liquid chromatography method using C8 column. The isocratic conditions using acetonitrile, methanol, water, and tetrahydrofuran were applied. Fluorescence detection was performed at 365 nm (excitation) and 475 nm (emission) wavelengths. The total analysis time was 10 min. The validation results of the method (within-laboratory reproducibility 4.0% CV, mean recovery 100.1%) confirm the appropriate precision and accuracy of the developed method. PMID:24453835

  8. Determination of selected azaarenes in water by bonded-phase extraction and liquid chromatography

    Science.gov (United States)

    Steinheimer, T.R.; Ondrus, M.G.

    1986-01-01

    A method for the rapid and simple quantitative determination of quinoline, isoquinoline, and five selected three-ring azaarenes in water has been developed. The azaarene fraction is separated from its carbon analogues on n-octadecyl packing material by edition with acidified water/acetonitrile. Concentration as great as 1000-fold is achieved readily. Instrumental analysis involves high-speed liquid chromatography on flexible-walled, wide-bore columns with fluorescence and ultraviolet detection at several wavelengths employing filter photometers in series. Method-validation data is provided as azaarene recovery efficiency from fortified samples. Distilled water, river water, contaminated ground water, and secondary-treatment effluent have been tested. Recoveries at part-per-billion levels are nearly quantitative for the three-ring compounds, but they decrease for quinoline and isoquinoline. ?? 1986 American Chemical Society.

  9. ANALISIS RESIDU KLORPIRIFOS DALAM SAYUR-SAYURAN DENGAN TEKNIK HIGH PERFORMANCE LIQUID CHROMATOGRAPHY (HPLC

    Directory of Open Access Journals (Sweden)

    Aman Sentosa Panggabean

    2016-06-01

    Full Text Available The research about analysis of chlorpyrifos residue in vegetables by using High Performance Liquid Chromatography (HPLC technique has been done. To obtain the optimal measurement results, the measurement performed several important parameters in the chromatographic system was composition of mobile phase, volume injection sample, flow rate and pH eluent. Optimum measurement conditions obtained was mobile phase composition (water : methanol with 70 : 30, volume injection sample are 5 mL, flow rate are 0.5mL/menit and pH eluent are 7. The analytical performance that obtained is good showed with the reproducibility value as percentage coefficient variance (% CV was 0.0664%, limit of detection (LOD was 0.44 ppm, with a recovery percentage of > 95%. The results obtained showed the HPLC technique can be used for the routine analysis in the determination of chlorpyrifos for the vegetable samples. Keywords: Chlorpyrifos, Vegetables, HPLC.

  10. Quantitative determination of acetaminophen, phenylephrine and carbinoxamine in tablets by high-performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Carina de A. Bastos

    2009-01-01

    Full Text Available An alternative methodology for analysis of acetaminophen (Ace, phenylephrine (Phe and carbinoxamine (Car in tablets by ion-pair reversed phase high performance liquid chromatography was validated. The pharmaceutical preparations were analyzed by using a C18 column (5 μm, 300 mm, 3.9 mm and mobile phase consisting of 60% methanol and 40% potassium monobasic phosphate aqueous solution (62.46 mmol L-1 added with 1 mL phosphoric acid, 0.50 mL triethylamine and 0.25 g sodium lauryl sulfate. Isocratic analysis was performed under direct UV detection at 220 nm for Phe and Car and at 300 nm for Ace within 5 min.

  11. Phytochemical analysis of Hibiscus caesius using high performance liquid chromatography coupled with mass spectrometry.

    Science.gov (United States)

    Ain, Quratul; Naveed, Muhammad Na; Mumtaz, Abdul Samad; Farman, Muhammad; Ahmed, Iftikhar; Khalid, Nauman

    2015-09-01

    Various species in genus Hibiscus are traditionally known for their therapeutic attributes. The present study focused on the phytochemical analysis of a rather unexplored species Hibiscus caesius (H. caesius), using high-pressure liquid chromatography coupled with mass spectrometry (HPLC-MS). The analysis revealed five major compounds in the aqueous extract, viz. vanillic acid, protocatechoic acid, quercetin, quercetin glucoside and apigenin, being reported for the first time in H. caesius. Literature suggests that these compounds have important pharmacological traits such as anti-cancer, anti-inflammatory, anti-bacterial and hepatoprotective etc. however, this requires further pharmacological investigations at in vitro and in vivo scale. The above study concluded the medicinal potential of H. caesius.

  12. New insights into liquid chromatography for more eco-friendly analysis of pharmaceuticals.

    Science.gov (United States)

    Shaaban, Heba

    2016-10-01

    Greening the analytical methods used for analysis of pharmaceuticals has been receiving great interest aimed at eliminating or minimizing the amount of organic solvents consumed daily worldwide without loss in chromatographic performance. Traditional analytical LC techniques employed in pharmaceutical analysis consume tremendous amounts of hazardous solvents and consequently generate large amounts of waste. The monetary and ecological impact of using large amounts of solvents and waste disposal motivated the analytical community to search for alternatives to replace polluting analytical methodologies with clean ones. In this context, implementing the principles of green analytical chemistry (GAC) in analytical laboratories is highly desired. This review gives a comprehensive overview on different green LC pathways for implementing GAC principles in analytical laboratories and focuses on evaluating the greenness of LC analytical procedures. This review presents green LC approaches for eco-friendly analysis of pharmaceuticals in industrial, biological, and environmental matrices. Graphical Abstract Green pathways of liquid chromatography for more eco-friendly analysis of pharmaceuticals.

  13. Determination of methylparaben from cosmetic products by ultra performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    MANUELA M. MINCEA

    2009-06-01

    Full Text Available A new method for the determination of methylparaben by ultra-performance liquid chromatography (UPLC was developed. Methylparaben is often used as preservative, alone or in combination with other parabens, being added to cosmetic products, pharmaceutical products and foods to avoid microbial contamination. Due to its widespread use and potential risk to human health, assessing human exposure to this compound is of interest. A good determination and quantification of methylparaben was developed with a gradient elution using a mixture of methanol and water (60:40, v/v within 1.455 min. Under optimized conditions, the linear working range extends over two orders of magnitude with relative standard deviations of intra- and inter-day precision below 2.3 %, and a detection limit of 0.02 ng μL-1 for methylparaben. The proposed method was successfully applied to the assay of methylparaben in cosmetic products with minimal sample preparation.

  14. Characterization of Isomeric Glycans by Reversed Phase Liquid Chromatography-Electronic Excitation Dissociation Tandem Mass Spectrometry

    Science.gov (United States)

    Tang, Yang; Wei, Juan; Costello, Catherine E.; Lin, Cheng

    2018-04-01

    The occurrence of numerous structural isomers in glycans from biological sources presents a severe challenge for structural glycomics. The subtle differences among isomeric structures demand analytical methods that can provide structural details while working efficiently with on-line glycan separation methods. Although liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a powerful tool for mixture analysis, the commonly utilized collision-induced dissociation (CID) method often does not generate a sufficient number of fragments at the MS2 level for comprehensive structural characterization. Here, we studied the electronic excitation dissociation (EED) behaviors of metal-adducted, permethylated glycans, and identified key spectral features that could facilitate both topology and linkage determinations. We developed an EED-based, nanoscale, reversed phase (RP)LC-MS/MS platform, and demonstrated its ability to achieve complete structural elucidation of up to five structural isomers in a single LC-MS/MS analysis. [Figure not available: see fulltext.

  15. [Systematic evaluation of retention behavior of carbohydrates in hydrophilic interaction liquid chromatography].

    Science.gov (United States)

    Fu, Qing; Wang, Jun; Liang, Tu; Xu, Xiaoyong; Jin, Yu

    2013-11-01

    A systematic evaluation of retention behavior of carbohydrates in hydrophilic interaction liquid chromatography (HILIC) was performed. The influences of mobile phase, stationary phase and buffer salt on the retention of carbohydrates were investigated. According to the results, the retention time of carbohydrates decreased as the proportion of acetonitrile in mobile phase decreased. Increased time of carbohydrates was observed as the concentration of buffer salt in mobile phase increased. The retention behavior of carbohydrates was also affected by organic solvent and HILIC stationary phase. Furthermore, an appropriate retention equation was used in HILIC mode. The retention equation lnk = a + blnC(B) + cC(B) could quantitatively describe the retention factors of carbohydrates of plant origin with good accuracy: the relative error of the predicted time to actual time was less than 0.3%. The evaluation results could provide guidance for carbohydrates to optimize the experimental conditions in HILIC method development especially for carbohydrate separation

  16. Longitudinal On-Column Thermal Modulation for Comprehensive Two-Dimensional Liquid Chromatography.

    Science.gov (United States)

    Creese, Mari E; Creese, Mathew J; Foley, Joe P; Cortes, Hernan J; Hilder, Emily F; Shellie, Robert A; Breadmore, Michael C

    2017-01-17

    Longitudinal on-column thermal modulation for comprehensive two-dimensional liquid chromatography is introduced. Modulation optimization involved a systematic investigation of heat transfer, analyte retention, and migration velocity at a range of temperatures. Longitudinal on-column thermal modulation was realized using a set of alkylphenones and compared to a conventional valve-modulator employing sample loops. The thermal modulator showed a reduced modulation-induced pressure impact than valve modulation, resulting in reduced baseline perturbation by a factor of 6; yielding a 6-14-fold improvement in signal-to-noise. A red wine sample was analyzed to demonstrate the potential of the longitudinal on-column thermal modulator for separation of a complex sample. Discrete peaks in the second dimension using the thermal modulator were 30-55% narrower than with the valve modulator. The results shown herein demonstrate the benefits of an active focusing modulator, such as reduced detection limits and increased total peak capacity.

  17. Determination of dapsone in meat and milk by liquid chromatography tandem mass spectrometry

    International Nuclear Information System (INIS)

    Hadjigeorgiou, M.; Papachrysostomou, Ch.; Theodorou, Z.; Kanari, P.; Constantinou, S.

    2009-01-01

    Within the EU the use of dapsone (4,4-diaminodiphenylsulfone) is prohibited in food-producing animals and consequently it's included in the Annex IV of the Directive 90/2377/EC. A quantitative confirmatory method has been developed and validated according to the criteria defined in the Commission Decision 2002/657/EC, for the determination of dapsone in meat and milk. Samples, after homogenization in alkaline conditions and organic solvent extraction, were purified on silica gel solid phase extraction cartridges. The eluate was evaporated and redissolved in mobile phase and was analysed by liquid chromatography tandem mass spectrometry (LC-MS/MS) in positive electrospray ionisation (ESI) using deuterium labelled Sulphadimidine-d7 as internal standard. The calculated value for, decision limit, CCα is 0.12 μg kg -1 , and the detection capability; CCβ value is 0.16 μg kg -1

  18. Development of High Performance Liquid Chromatography and Mass Spectrometry: a Key Engine of TCM Modernization

    Directory of Open Access Journals (Sweden)

    Zheng-Xiang Zhang

    2015-04-01

    Full Text Available Traditional Chinese Medicine (TCM has been popular for thousand years in prevention and treatment of chronic diseases synergistically with Western medicine while producing mild healing effects and lower side effects. Although many TCMs have been proven effective by modern pharmacological studies and clinical trials, their bioactive constituents and the remedial mechanisms are still not well understood. Researchers have made great efforts to explore the real theory of TCM for many years with different strategies. Development of high performance liquid chromatography (HPLC and mass spectrometry within recent decade can provide scientists with robust technologies for disclosing the mysterious mask of TCM. In this paper, important innovations of HPLC and mass spectrometry are reviewed in the application of TCM analysis from single compound identification to metabolomic strategy.

  19. A high performance liquid chromatography method for determination of furfural in crude palm oil.

    Science.gov (United States)

    Loi, Chia Chun; Boo, Huey Chern; Mohammed, Abdulkarim Sabo; Ariffin, Abdul Azis

    2011-09-01

    A modified steam distillation method was developed to extract furfural from crude palm oil (CPO). The collected distillates were analysed using high performance liquid chromatography (HPLC) coupled with an ultraviolet diode detector at 284nm. The HPLC method allowed identification and quantification of furfural in CPO. The unique thermal extraction of CPO whereby the fresh fruit bunches (FFB) are first subjected to steam treatment, distinguishes itself from other solvent-extracted or cold-pressed vegetable oils. The presence of furfural was also determined in the fresh palm oil from FFB (without undergoing the normal extraction process), palm olein, palm stearin, olive oil, coconut oil, sunflower oil, soya oil and corn oil. The chromatograms of the extracts were compared to that of standard furfural. Furfural was only detected in CPO. The CPO consignments obtained from four mills were shown to contain 7.54 to 20.60mg/kg furfural. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. Determination of adenosine phosphates in rat gastrocnemius at various postmortem intervals using high performance liquid chromatography.

    Science.gov (United States)

    Huang, Hong; Yan, Youyi; Zuo, Zhong; Yang, Lin; Li, Bin; Song, Yu; Liao, Linchuan

    2010-09-01

    Although the change in adenosine phosphate levels in muscles may contribute to the development of rigor mortis, the relationship between their levels and the onset and development of rigor mortis has not been well elucidated. In the current study, levels of the adenosine phosphates including adenosine triphosphate (ATP), adenosine diphosphate (ADP), and adenosine monophosphate (AMP) in gastrocnemius at various postmortem intervals of 180 rats from different death modes were detected by high performance liquid chromatography. The results showed that the levels of ATP and ADP significantly decreased along with the postmortem period of rats from different death mode whereas the AMP level remained the same. In addition, it was found that changes in the ATP levels in muscles after death correlated well with the development of rigor mortis. Therefore, the ATP level could serve as a reference parameter for the deduction of rigor mortis in forensic science.

  1. Quantitative analysis of urine vapor and breath by gas-liquid partition chromatography.

    Science.gov (United States)

    Pauling, L; Robinson, A B; Teranishi, R; Cary, P

    1971-10-01

    When a human being is placed for several days on a completely defined diet, consisting almost entirely of small molecules that are absorbed from the stomach into the blood, intestinal flora disappear because of lack of nutrition. By this technique, the composition of body fluids can be made constant (standard deviation about 10%) after a few days, permitting significant quantitative analyses to be performed. A method of temperature-programmed gas-liquid partition chromatography has been developed for this purpose. It permits the quantitative determination of about 250 substances in a sample of breath, and of about 280 substances in a sample of urine vapor. The technique should be useful in the application of the principles of orthomolecular medicine.

  2. Determination of oxymatrine in Sophora Radix by high performance liquid chromatography

    International Nuclear Information System (INIS)

    Yang, Seung Kwon; Yun, Young Ja; Namgung, Mi Ok

    2004-01-01

    A high performance liquid chromatographic method was designed for the quantitative analysis of oxymatrine in Sophora Radix. The separation of oxymatrine was performed by reversed-phase chromatography with a C 18 column and a buffered aqueous solution containing acetonitrile, and monitored by UV absorption at 215 nm. Extraction of oxymatrine in Sophora Radix was carried out using various solvents and extraction methods. The optimum extraction efficiency for the crushed Sophora Radix was achieved by reflux at 80 .deg. C in 50% ethanol for five hours. Most extraction methods used to complicate pretreatments. In this study, sublimation was employed for a extraction method without going through complicate pretreatments. Sublimation was carried out under high vacuum (1x10 -3 torr) and at high temperature (200 .deg. C). Extraction efficiency using Sublimation was found to be inferior to other extraction methods

  3. Cation exchange separation of 16 rare earth metals by microscale high-performance liquid chromatography

    International Nuclear Information System (INIS)

    Ishii, D.; Hirose, A.; Iwasaki, Y.

    1978-01-01

    The separation of rare earth metals has been studied with a microcolumn of 0.5 mm i.d. and 75 mm length, packed with TSK LS-212 high-performance cation exchange resin. A micro-feeder (Model MF-2, from Azumadenki Kogyo) was used to drive carrier and sample solutions through the ion exchange column and detection cell. By combining a 250 μl syringe and a 0.5 mm i.d. sampling tube the micro-feeder, 0.1-1.0 μl rare earth metals were separated within 38 min, using only 304 μl of 0.4M α-hydroxy-isobutyric acid solution adjusted to pH 3.1-6.0 with ammonia solution as gradient carrier solution. The gradient elution was successfully performed by applying a new technique developed for microscale liquid chromatography. (author)

  4. Quantification of sulphur amino acids by ultra-high performance liquid chromatography in aquatic invertebrates.

    Science.gov (United States)

    Thera, Jennifer C; Kidd, Karen A; Dodge-Lynch, M Elaine; Bertolo, Robert F

    2017-12-15

    We examined the performance of an ultra-high performance liquid chromatography method to quantify protein-bound sulphur amino acids in zooplankton. Both cysteic acid and methionine sulfone were linear from 5 to 250 pmol (r 2  = 0.99), with a method detection limit of 13 pmol and 9 pmol, respectively. Although there was no matrix effect on linearity, adjacent peaks and co-eluting noise from the invertebrate proteins increased the detection limits when compared to common standards. Overall, performance characteristics were reproducible and accurate, and provide a means for quantifying sulphur amino acids in aquatic invertebrates, an understudied group. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Core-Shell Columns in High-Performance Liquid Chromatography: Food Analysis Applications

    Science.gov (United States)

    Preti, Raffaella

    2016-01-01

    The increased separation efficiency provided by the new technology of column packed with core-shell particles in high-performance liquid chromatography (HPLC) has resulted in their widespread diffusion in several analytical fields: from pharmaceutical, biological, environmental, and toxicological. The present paper presents their most recent applications in food analysis. Their use has proved to be particularly advantageous for the determination of compounds at trace levels or when a large amount of samples must be analyzed fast using reliable and solvent-saving apparatus. The literature hereby described shows how the outstanding performances provided by core-shell particles column on a traditional HPLC instruments are comparable to those obtained with a costly UHPLC instrumentation, making this novel column a promising key tool in food analysis. PMID:27143972

  6. Identification of glycosaminoglycans using high-performance liquid chromatography on a hydroxyapatite column.

    Science.gov (United States)

    Narita, H; Takeda, Y; Takagaki, K; Nakamura, T; Harata, S; Endo, M

    1995-11-20

    Glycosaminoglycans (heparin, heparan sulfate, dermatan sulfate, chondroitin sulfate, and hyaluronic acid) were labeled with a fluorescent reagent, 2-aminopyridine. The fluoro-labeled glycosaminoglycans were subjected to high-performance liquid chromatography on a hydroxyapatite column. The binding property of each glycosaminoglycan to hydroxyapatite was different. The structural properties of glycosaminoglycans bound to hydroxyapatite were then investigated using chemical desulfated or enzymic depolymerized glycosaminoglycans. This revealed that the sulfate content and molecular weight of the glycosaminoglycans correlated with their binding properties to hydroxyapatite. Desulfated dermatan sulfate but not desulfated chondroitin 6-sulfate bound to the hydroxyapatite. These data indicate that iduronic acid residues of glycosaminoglycans are important for the binding property. The method described which uses hydroxyapatite columns facilitates rapid separation and microanalysis of the glycosaminoglycans, especially dermatan sulfate and chondroitin sulfate.

  7. Determination of clarithromycin in human plasma by liquid chromatography-electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Jiang, Yao; Wang, Jiang; Li, Hao; Wang, Yingwu; Gu, Jingkai

    2007-03-12

    A rapid and sensitive method has been developed for the determination of clarithromycin in human plasma with liquid chromatography-tandem mass spectrometry. Clarithromycin and the internal standard, telmisartan were precipitated from the matrix (50 microl) with 200 microl acetonitrile and separated by HPLC using formic acid:10 mM ammonium acetate:methanol (1:99:400, v/v/v) as the mobile phase. The assay based on detection by electrospray positive ionization mass spectrometry in the multiple-reaction monitoring mode was finished within 2.4 min. Linearity was over the concentration range 10-5000 ng/ml with a limit of detection of 0.50 ng/ml. Intra- and inter-day precision measured as relative standard deviation were bioequivalence study of two tablet formulations of clarithromycin.

  8. Burn-up measurements on nuclear reactor fuels using high performance liquid chromatography

    International Nuclear Information System (INIS)

    Sivaraman, N.; Subramaniam, S.; Srinivasan, T.G.; Vasudeva Rao, P.R.

    2002-01-01

    Burn-up measurements on thermal as well as fast reactor fuels were carried out using high performance liquid chromatography (HPLC). A column chromatographic technique using di-(2-ethylhexyl) phosphoric acid (HDEHP) coated column was employed for the isolation of lanthanides from uranium, plutonium and other fission products. Ion-pair HPLC was used for the separation of individual lanthanides. The atom percent fissions were calculated from the concentrations of the lanthanide (neodymium in the case of thermal reactor and lanthanum for the fast reactor fuels) and from uranium and plutonium contents of the dissolver solutions. The HPLC method was also used for determining the fractional fissions from uranium and plutonium for the thermal reactor fuel. (author)

  9. High-performance liquid chromatography for determination of α-tocopherol in vegetables

    Directory of Open Access Journals (Sweden)

    Marcin Horbowicz

    2013-12-01

    Full Text Available A simple method for the determination of α-tocopherol in vegetables is described. The procedure consists of the following steps: saponification, extraction, silica-column clean-up, and high-performance liquid chromatography. Elution time for D, L-α-tocopherol was 9.0 min using a Zorbax Sil (250 x 4.6 mm column and an isocratic mobile phase of hexane-methanol (99.3 + 0.7, with a flow rate of 1 ml/min, and detection at 292 nm using a variable UV detector. The average recovery of α-tocopherol was 91.2%, and the minimum detectable amount was 0.1 mg/100 g of fresh vegetable tissue. This method is comparable to gas-chromatographic determination of α-tocopherol, but has fewer analytical steps and gives more reproducible results.

  10. [Application of liquid chromatography-high resolution mass spectrometry in toxicological screening].

    Science.gov (United States)

    Li, Xiao-Wen; Shen, Bao-Hua; Zhuo, Xian-Yi

    2011-10-01

    Due to the diversity of toxicologically relevant substances, the uncertainty of target compounds and the specificity of samples, toxicological screening techniques have always been valued by the forensic toxicologists. Depending on its powerful separation ability, superhigh resolution and accurate mass measurement, combined with the two levels spectrum database matching and abundance ratio of isotope ion, the liquid chromatography-high resolution mass spectrometry (LC-HRMS) analyzers have increasingly advantage in screening and identification of chemical compound. This review focuses on the applications of LC-HRMS in screening and identification of drug-of-abuse, prescription drugs, pesticide and stimulant. The prospect of LC-HRMS in forensic toxicology analysis is also included.

  11. SIMULTANEOUS DETERMINATION OF PARACETAMOL AND IBUPROFENE MIXTURES BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

    Directory of Open Access Journals (Sweden)

    Sophi Damayanti

    2010-06-01

    Full Text Available Analytical method for the determination of paracetamol and ibuprofene mixtures has been developed by High Performance Liquid Chromatography using C-18 column and acetinitrile - phosphate buffer pH = 4.5 (75:25 containing 0.075% sodium hexanesulfunate as a mobile phase. The detector was set at 215 nm. Using such conditions, retention time for paracetamol and ibuprofen was 4.89 and 7.11 min, respectively. The recovery for paracetamol and ibuprofen was found to be 101.07± 0.73% and 102.02 ± 1.58%, respectively. The detector limits of the method was 1.30 and 1.60 μg/mL with the relative standard deviation (RSD 0.74 and 1.52% for paracetamol and ibuprofen, respectively.   Keywords: paracetamol, ibuprofen, multi-component, validation, HPLC.

  12. Determination of phenmedipham and desmedipham in a commercial herbicide by high performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Lončar Eva S.

    2004-01-01

    Full Text Available Betanal AM-11 is the herbicide that is using to control one-year old weeds with wide leafs in sugar beet fields. Active ingredients of the herbicide are phenmedipham and desmedipham. Commercial emulsifiable concentrate (EC contains 80 g/L ( 10% of each active compound. We applied high performance liquid chromatography (HPLC with diode array detector (DAD at 254 nm for the determination of phenmedipham and desmedipham in commercial samples of Betanal AM-11. This method involves reversed-phase separation of the components on C-18 bonded silica with methanol-water (51+49, v/v as the eluent. The procedure was highly selective and reproducible and can be successfully used in determining contents of phenmedipham and desmedipham on micro and macro levels.

  13. Determination of free urinary cortisol in cushing's syndrome using reversed-phase high performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Eduardo Kinio Sugawara

    2010-01-01

    Full Text Available Determination of free urinary cortisol is a test of choice in the diagnosis of Cushing's syndrome. In this study, cortisol was quantified using reversed-phase high-performance liquid chromatography (RP-HPLC in urine samples previously extracted with ether and using triamcinolone acetonide as internal standard (IS. A BDS-Hypersil-C18® column, water-acetonitrile (72:28; v/v, with a flow rate of 1.0 mL/min and detection at 243 nm were used. This method showed to be both effective and efficient, with sensitivity and linearity ranging from 2.50 to 150 μg/L, and can be used in substitution to the radioimmunoassay technique within this concentration range.

  14. Recent advances of liquid chromatography-(tandem) mass spectrometry in clinical and forensic toxicology.

    Science.gov (United States)

    Peters, Frank T

    2011-01-01

    Liquid chromatography (LC) coupled to mass spectrometry (MS) or tandem mass spectrometry (MS/MS) has become increasingly important in clinical and forensic toxicology as well as doping control and is now a robust and reliable technique for routine analysis in these fields. In recent years, methods for LC-MS(/MS)-based systematic toxicological analysis using triple quadrupole or ion trap instruments have been considerably improved and a new screening approach based on high-resolution MS analysis using benchtop time-of-flight MS instruments has been developed. Moreover, many applications for so-called multi-target screening and/or quantification of drugs, poisons, and or their metabolites in various biomatrices have been published. The present paper will provide an overview and discuss these recent developments focusing on the literature published after 2006. Copyright © 2010 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  15. Development of high performance liquid chromatography for rapid determination of burn-up of nuclear fuels

    International Nuclear Information System (INIS)

    Joseph, M.; Karunasagar, D.; Saha, B.

    1996-01-01

    Burn-up an important parameter during evaluation of the performance of any nuclear fuel. Among the various techniques available, the preferred one for its determination is based on accurate measurement of a suitable fission product monitor and the residual heavy elements. Since isotopes of rare earth elements are generally used as burn-up monitors, conditions were standardized for rapid separation (within 15 minutes) of light rare earths using high performance liquid chromatography based on either anion exchange (Partisil 10 SAX) in methanol-nitric acid medium or by cation exchange on a reverse phase column (Spherisorb 5-ODS-2 or Supelcosil LC-18) dynamically modified with 1-octane sulfonate or camphor-10-sulfonic acid (β). Both these methods were assessed for separation of individual fission product rare earths from their mixtures. A new approach has been examined in detail for rapid assay of neodymium, which appears promising for faster and accurate measurement of burn-up. (author)

  16. High performance liquid chromatography method for the determination of cinnamyl alcohol dehydrogenase activity in soybean roots.

    Science.gov (United States)

    dos Santos, W D; Ferrarese, Maria de Lourdes Lucio; Ferrarese-Filho, O

    2006-01-01

    This study proposes a simple, quick and reliable method for determining the cinnamyl alcohol dehydrogenase (CAD; EC 1.1.1.195) activity in soybean (Glycine max L. Merr.) roots using reversed-phase high performance liquid chromatography (RP-HPLC). The method includes a single extraction of the tissue and conduction of the enzymatic reaction at 30 degrees C with cinnamaldehydes (coniferyl or sinapyl), substrates of CAD. Disappearance of the substrates in the reaction mixture is monitored at 340 nm (for coniferaldehyde) or 345 nm (for sinapaldehyde) by isocratic elution with methanol/acetic acid through a GLC-ODS (M) column. This HPLC technique furnishes a rapid and reliable measure of cinnamaldehyde substrates, and may be used as an alternative tool to analyze CAD activity in enzyme preparation without previous purification.

  17. Determination of rare earth elements by liquid chromatography/inductively coupled plasma atomic emission spectrometry

    International Nuclear Information System (INIS)

    Yoshida, K.; Haraguchi, H.

    1984-01-01

    Inductively coupled plasma atomic emission spectrometry (ICP-AES) interfaced with high-performance liquid chromatography (HPLC) has been applied to the determination of rare earth elements. ICP-AES was used as an element-selective detector for HPLC. The separation of rare earth elements with HPLC helped to avoid erroneous analytical results due to spectral interferences. Fifteen rare earth elements (Y and 14 lanthanides) were determined selectively with the HPLC/ICP-AES system using a concentration gradient method. The detection limits with the present HPLC/ICP-AES system were about 0.001-0.3 μg/mL with a 100-μL sample injection. The calibration curves obtained by the peak height measurements showed linear relationships in the concentration range below 500 μg/mL for all rare earth elements. A USGS rock standard sample, rare earth ores, and high-purity lanthanide reagents (>99.9%) were successfully analyzed without spectral interferences

  18. Discrimination of Black Ball-point Pen Inks by High Performance Liquid Chromatography (HPLC)

    International Nuclear Information System (INIS)

    Mohamed Izzharif Abdul Halim; Norashikin Saim; Rozita Osman; Halila Jasmani; Nurul Nadhirah Zainal Abidin

    2013-01-01

    In this study, thirteen types of black ball-point pen inks of three major brands were analyzed using high performance liquid chromatography (HPLC). Separation of the ink components was achieved using Bondapak C-18 column with gradient elution using water, ethanol and ethyl acetate. The chromatographic data obtained at wavelength 254.8 nm was analyzed using agglomerative hierarchical clustering (AHC) and principle component analysis (PCA). AHC was able to group the inks into three clusters. This result was supported by PCA, whereby distinct separation of the three different brands was achieved. Therefore, HPLC in combination with chemometric methods may be a valuable tool for the analysis of black ball-point pen inks for forensic purposes. (author)

  19. [Detection of the preservative chlorphenesin in cosmetics by high-performance liquid chromatography].

    Science.gov (United States)

    Ikarashi, Yoshiaki; Miyazawa, Norimasa; Shimamura, Kimio; Sato, Nobuo; Yoshizawa, Ken-ichi; Hayashi, Masahito; Takano, Katsuhiro; Miyamoto, Michiko; Kojima, Takashi; Sakaguchi, Hiroshi; Fujiio, Makiko

    2009-01-01

    A simple determination method for preservative chlorphenesin in cosmetics was developed. Cosmetic samples were dissolved in methanol. The sample solution was analyzed by high-performance liquid chromatography (HPLC) with ODS column, using water-methanol (55:45) or water-acetonitrile (3:1) adjusted to pH 2.5 with phosphoric acid as the mobile phase. Chlorphenesin was detected with ultraviolet light detection at 280 nm. A linear relation was obtained between the peak areas and the concentrations of chlorphenesin in the range of 1-500 microg/ml. The determination limit of chlorphenesin was 1-2 microg/ml. Recoveries of chlorphenesin spiked in lotion and milky lotion at the levels of 0.03% and 0.3% were 98.8-100.0%. This method was applied for cosmetics including 0.03% and 0.3% of chlorphenesin and their content corresponded with the determined values.

  20. [Analysis of the preservative chlorphenesin in cosmetics by high performance liquid chromatography].

    Science.gov (United States)

    Zhu, Huijuan; Zhang, Weiqiang; Yang, Yanwei; Zhu, Ying

    2014-01-01

    An analytical method was developed for the determination of the preservative of chlorphenesin in cosmetics by high performance liquid chromatography (HPLC). A C18 column (250 mm x 4.6 mm, 5 microm) and a photodiode array detector were used. The mobile phase was methanol-water (55:45, v/v) with a flow rate of 1.0 mL/min. The detection wavelength was set at 280 nm and the column temperature was 25 degrees C. The limit of detection was 3 ng. A good linear relationship was obtained between the peak area and the mass concentration of chlorphenesin in the range of 1 - 500 mg/L and the correlation coefficient was 1.000 0. The recoveries of chlorphenesin at different spiked levels were 99.0% - 103% with the relative standard deviations (RSD) chlorphenesin in cosmetics.

  1. Liquid chromatography-mass spectrometry identification of anthocyanins of isla oca (Oxalis tuberosa, Mol.) tubers.

    Science.gov (United States)

    Alcalde-Eon, Cristina; Saavedra, Gloria; de Pascual-Teresa, Sonia; Rivas-Gonzalo, Julián C

    2004-10-29

    High-performance liquid chromatography (HPLC)-diode array detection (DAD)-mass spectrometry (MS) techniques have been successfully employed in the identification of the anthocyanins of the coloured tubers of isla oca (Oxalis tuberosa), the second most cultivated tuber in the Andean region. Tubers underwent a pre-treatment step in order to inhibit enzymatic reactions and to obtain a stable powder or "concentrate". This concentrate was dissolved, purified and then analysed. Eight different compounds were found. The major peaks were malvidin glucosides (malvidin 3-O-glucoside and 3,5-O-diglucoside). The rest of the peaks were 3,5-O-diglucosides of petunidin and peonidin, and 3-O-glucosides of delphinidin, petunidin and peonidin. Only malvidin 3-O-acetylglucoside-5-O-glucoside was found as an acylated anthocyanin.

  2. [Determination of aspirin and free salicylic acid in lysinipirine injection by high performance liquid chromatography].

    Science.gov (United States)

    Dong, Yu; Zhao, Yuan-zheng; Zhang, Yi-na

    2002-05-01

    The contents of aspirin and free salicylic acid in lysinipirine injection were determined by high performance liquid chromatography (HPLC). A Hypersil BDS C18 column was used with the mobile phase of methanol-water-acetic acid (35:65:3, volume ratio) and the detection wavelength of 280 nm. The average recoveries of aspirin and salicylic acid added were 99.27% (RSD = 0.8%) and 99.61%(RSD = 1.3%), respectively. The calibration curves had good linearity in the range of 0.028 g/L -0.141 mg/L and 0.77 mg/L -3.85 mg/L, and the correlation coefficients were 0.9999 and 0.9998 for aspirin and salicylic acid respectively.

  3. [Determination of glycyrrhizinic acid in biotransformation system by reversed-phase high performance liquid chromatography].

    Science.gov (United States)

    Li, Hui; Lu, Dingqiang; Liu, Weimin

    2004-05-01

    A method for determining glycyrrhizinic acid in the biotransformation system by reversed-phase high performance liquid chromatography (RP-HPLC) was developed. The HPLC conditions were as follows: Hypersil C18 column (4.6 mm i.d. x 250 mm, 5 microm) with a mixture of methanol-water-acetic acid (70:30:1, v/v) as the mobile phase; flow rate at 1.0 mL/min; and UV detection at 254 nm. The linear range of glycyrrhizinic acid was 0.2-20 microg. The recoveries were 98%-103% with relative standard deviations between 0.16% and 1.58% (n = 3). The method is simple, rapid and accurate for determining glycyrrhizinic acid.

  4. Determination of trimethoprim in tissues using liquid chromatography-thermospray mass spectrometry.

    Science.gov (United States)

    Cannavan, A; Hewitt, S A; Floyd, S D; Kennedy, D G

    1997-11-01

    A method is described for the determination of the antibacterial drug trimethoprim in tissues. Minced tissue is homogenised with chloroform-acetone (1 + 1 v/v), filtered, and the filtrate evaporated to an oily residue using a rotary evaporator. The residue is redissolved in methanol-water-acetic acid (50 + 48.7 + 1.3 v/v) and any fats present are partitioned into hexane. The aqueous phase is analysed by liquid chromatography-thermospray mass spectrometry in positive mode with the protonated molecular ion at m/z 291 being monitored. Recoveries ranged between 60% in liver and 79% in muscle. The limit of determination was 25 micrograms kg-1 and the limit of detection was approximately 4 micrograms kg-1. The method is suitable for monitoring tissues taken under national surveillance schemes for veterinary drug residues.

  5. Application of liquid chromatography-electrospray ionization mass spectrometry for study of steroid-converting enzymes.

    Science.gov (United States)

    Miksík, Ivan; Mikulíková, Katerina; Pácha, Jirí; Kucka, Marek; Deyl, Zdenek

    2004-02-05

    A high-performance liquid chromatography-atmospheric pressure ionization-electrospray ionization mass spectrometry (HPLC-API-ESI-MS) method was developed for the analysis of steroids in a study of steroid-converting enzymes. Separations ware done on a Zorbax Eclipse XDB-C18 column (eluted with a linear methanol-water-acetic acid gradient) and identification of the steroids involved was done by API-ESI-MS using positive ion mode and extracted ion analysis. The applicability of the present method for studying steroid metabolism was proven in assaying two steroid-converting enzymes (20beta-hydroxysteroid dehydrogenase and 11beta-hydroxysteroid dehydrogenase) in various biological samples (rat and chicken intestine, chicken oviduct).

  6. Measurement of food flavonoids by high-performance liquid chromatography: A review.

    Science.gov (United States)

    Merken, H M; Beecher, G R

    2000-03-01

    The flavonoids are plant polyphenols found frequently in fruits, vegetables, and grains. Divided into several subclasses, they include the anthocyanidins, pigments chiefly responsible for the red and blue colors in fruits, fruit juices, wines, and flowers; the catechins, concentrated in tea; the flavanones and flavanone glycosides, found in citrus and honey; and the flavones, flavonols, and flavonol glycosides, found in tea, fruits, vegetables, and honey. Known for their hydrogen-donating antioxidant activity as well as their ability to complex divalent transition metal cations, flavonoids are propitious to human health. Computer-controlled high-performance liquid chromatography (HPLC) has become the analytical method of choice. Many systems have been developed for the detection and quantification of flavonoids across one, two, or three subclasses. A summary of the various HPLC and sample preparation methods that have been employed to quantify individual flavonoids within a subclass or across several subclasses are tabulated in this review.

  7. Quantification of cardiolipin by liquid chromatography-electrospray ionization mass spectrometry.

    Science.gov (United States)

    Garrett, Teresa A; Kordestani, Reza; Raetz, Christian R H

    2007-01-01

    Cardiolipin (CL), a tetra-acylated glycerophospholipid composed of two phosphatidyl moieties linked by a bridging glycerol, plays an important role in mitochondrial function in eukaryotic cells. Alterations to the content and acylation state of CL cause mitochondrial dysfunction and may be associated with pathologies such as ischemia, hypothyrodism, aging, and heart failure. The structure of CL is very complex because of microheterogeneity among its four acyl chains. Here we have developed a method for the quantification of CL molecular species by liquid chromatography-electrospray ionization mass spectrometry. We quantify the [M-2H](2-) ion of a CL of a given molecular formula and identify the CLs by their total number of carbons and unsaturations in the acyl chains. This method, developed using mouse macrophage RAW 264.7 tumor cells, is broadly applicable to other cell lines, tissues, bacteria and yeast. Furthermore, this method could be used for the quantification of lyso-CLs and bis-lyso-CLs.

  8. Characterization of free and bound fatty acids in human gallstones by capillary gas liquid chromatography

    International Nuclear Information System (INIS)

    Channa, N.A.; Khand, F.D.; Noorani, M.A.; Bhanger, M.I.

    2002-01-01

    Forty-four human gallstone samples either of pure cholesterol or cholesterol and bilirubin were randomly selected and analyzed by capillary gas liquid chromatography for the relative percentage composition of free and total fatty acids. The results showed that bound fatty acids were present in higher amounts than the free fatty acids. Amongst the bound fatty acids the percentage occurrence for palmitic acid was highest followed by stearic, oleic, linoleic and myristic acids. Fatty acids myristic, palmitic and linoleic were present in higher amounts in cholesterol gallstones, whereas stearic acid in cholesterol and bilirubin gallstones. When compared, no significant difference (p < 0.05) in the levels of free and bound fatty acids were seen in gallstones of males and females. The results suggest that bound fatty acids have a role to play in the structure of gallstones. (author)

  9. High-throughput liquid chromatography for drug analysis in biological fluids: investigation of extraction column life.

    Science.gov (United States)

    Zeng, Wei; Fisher, Alison L; Musson, Donald G; Wang, Amy Qiu

    2004-07-05

    A novel method was developed and assessed to extend the lifetime of extraction columns of high-throughput liquid chromatography (HTLC) for bioanalysis of human plasma samples. In this method, a 15% acetic acid solution and 90% THF were respectively used as mobile phases to clean up the proteins in human plasma samples and residual lipids from the extraction and analytical columns. The 15% acetic acid solution weakens the interactions between proteins and the stationary phase of the extraction column and increases the protein solubility in the mobile phase. The 90% THF mobile phase prevents the accumulation of lipids and thus reduces the potential damage on the columns. Using this novel method, the extraction column lifetime has been extended to about 2000 direct plasma injections, and this is the first time that high concentration acetic acid and THF are used in HTLC for on-line cleanup and extraction column lifetime extension.

  10. Development of high performance liquid chromatography method for miconazole analysis in powder sample

    Science.gov (United States)

    Hermawan, D.; Suwandri; Sulaeman, U.; Istiqomah, A.; Aboul-Enein, H. Y.

    2017-02-01

    A simple high performance liquid chromatography (HPLC) method has been developed in this study for the analysis of miconazole, an antifungal drug, in powder sample. The optimized HPLC system using C8 column was achieved using mobile phase composition containing methanol:water (85:15, v/v), a flow rate of 0.8 mL/min, and UV detection at 220 nm. The calibration graph was linear in the range from 10 to 50 mg/L with r 2 of 0.9983. The limit of detection (LOD) and limit of quantitation (LOQ) obtained were 2.24 mg/L and 7.47 mg/L, respectively. The present HPLC method is applicable for the determination of miconazole in the powder sample with a recovery of 101.28 % (RSD = 0.96%, n = 3). The developed HPLC method provides short analysis time, high reproducibility and high sensitivity.

  11. Detailed molecular characterization of castor oil ethoxylates by liquid chromatography multistage mass spectrometry.

    Science.gov (United States)

    Nasioudis, Andreas; van Velde, Jan W; Heeren, Ron M A; van den Brink, Oscar F

    2011-10-07

    The molecular characterization of castor oil ethoxylates (CASEOs) was studied by reverse-phase liquid chromatography (RPLC) mass spectrometry (MS) and multistage mass spectrometry (MS(n)). The developed RPLC method allowed the separation of the various CASEO components, and especially, the baseline separation of multiple nominal isobars (same nominal mass) and isomers (same exact mass). MS and MS(n) were used for the determination and structure elucidation of various structures and for the discrimination of the isobars and isomers. Different ionization techniques and adduct ions were also tested for optimization of the MS detection and the MS(n) fragmentation. A unique fragmentation pathway of ricinoleic acid is proposed, which can be used as a marker of the polymerization process and the topology of ethoxylation in the CASEO. In addition, characteristic neutral losses of ricinoleic acid reveal its (terminal or internal) position in the molecule. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Determination of 6-mercaptopurine and azathioprine in plasma by high-performance liquid chromatography.

    Science.gov (United States)

    Ding, T L; Benet, L Z

    1979-07-21

    Using 1-ml plasma samples, levels of 6-mercaptopurine (6MP) as low as 5 ng/ml and azathioprine (AZA) as low as 40 ng/ml can be detected using a high-performance liquid chromatography reversed-phase column procedure following extraction. Both compounds were stable in frozen plasma for seven weeks. AZA stability in blood was temperature dependent; the half-lives of AZA breakdown to 6MP at 37 degrees were 28 and 46 min in blood drawn from two rhesus monkeys. Plasma levels of 6MP were measured in a rhesus monkey following 6MP (1.47 mg/kg) and AZA (3 mg/kg) intravenous administration. 6MP levels were also measured in three renal transplant patients on daily 50- and 100-mg AZA doses. Peak levels (45-75 ng/ml) were reached within an hour and 6MP levels were detected for up to 7 h.

  13. Analysis of bromate in drinking water using liquid chromatography-tandem mass spectrometry without sample pretreatment.

    Science.gov (United States)

    Kosaka, Koji; Asami, Mari; Takei, Kanako; Akiba, Michihiro

    2011-01-01

    An analytical method for determining bromate in drinking water was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The (18)O-enriched bromate was used as an internal standard. The limit of quantification (LOQ) of bromate was 0.2 µg/L. The peak of bromate was separated from those of coexisting ions (i.e., chloride, nitrate and sulfate). The relative and absolute recoveries of bromate in two drinking water samples and in a synthesized ion solution (100 mg/L chloride, 10 mg N/L nitrate, and 100 mg/L sulfate) were 99-105 and 94-105%, respectively. Bromate concentrations in 11 drinking water samples determined by LC-MS/MS were water without sample pretreatment.

  14. Determination of 15 isoflavone isomers in soy foods and supplements by high-performance liquid chromatography.

    Science.gov (United States)

    Yanaka, Kaoru; Takebayashi, Jun; Matsumoto, Teruki; Ishimi, Yoshiko

    2012-04-25

    Soy isoflavone is the generic name for the isoflavones found in soy. We determined the concentrations of 15 soy isoflavone species, including 3 succinyl glucosides, in 22 soy foods and isoflavone supplements by high-performance liquid chromatography (HPLC). The total isoflavone contents in 14 soy foods and 8 supplements ranged from 45 to 735 μg/g and from 1,304 to 90,224 μg/g, respectively. Higher amounts of succinyl glucosides were detected in natto, a typical fermented soy product in Japan; these ranged from 30 to 80 μg/g and comprised 4.1-10.9% of the total isoflavone content. In soy powder, 59 μg/g of succinyl glucosides were detected, equivalent to 4.6% of the total isoflavone content. These data suggest that the total isoflavone contents may be underestimated in the previous studies that have not included succinyl glucosides, especially for Bacillus subtilis -fermented soy food products.

  15. Robust optimization of psychotropic drug mixture separation in hydrophilic interaction liquid chromatography.

    Science.gov (United States)

    Rakić, Tijana; Jovanović, Marko; Dumić, Aleksandra; Pekić, Marina; Ribić, Sanja; Stojanović, Biljana Jancić

    2013-01-01

    This paper presents multiobjective optimization of complex mixtures separation in hydrophilic interaction liquid chromatography (HILIC). The selected model mixture consisted of five psychotropic drugs: clozapine, thioridazine, sulpiride, pheniramine and lamotrigine. Three factors related to the mobile phase composition (acetonitrile content, pH of the water phase and concentration of ammonium acetate) were optimized in order to achieve the following goals: maximal separation quality, minimal total analysis duration and robustness of an optimum. The consideration of robustness in early phases of the method development provides reliable methods with low risk for failure in validation phase. The simultaneous optimization of all goals was achieved by multiple threshold approach combined with grid point search. The identified optimal separation conditions (acetonitrile content 83%, pH of the water phase 3.5 and ammonium acetate content in water phase 14 mM) were experimentally verified.

  16. Determination of albendazole sulfoxide in human plasma by using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Saraner, Nihal; Özkan, Güler Yağmur; Güney, Berrak; Alkan, Erkin; Burul-Bozkurt, Nihan; Sağlam, Onursal; Fikirdeşici, Ezgi; Yıldırım, Mevlüt

    2016-06-01

    A rapid, simple and sensitive method was developed and validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for determination of albendazole sulfoxide (ABZOX) in human plasma. The plasma samples were extracted by protein precipitation using albendazole sulfoxide-d3 as internal standard (IS). The chromatographic separation was performed on Waters Xbridge C18Column (100×4.6mm, 3.5μm) with a mobile phase consisting of ammonia solution, water and methanol at a flow rate of 0.70mL/min. ABZOX was detected and identified by mass spectrometry with electrospray ionization (ESI) in positive ion and multiple-reaction monitoring (MRM) mode. The method was linear in the range of 3-1500ng/mL for ABZOX. This method was successfully applied to the bioequivalence study in human plasma samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Quality control of 99mTc-DTPA-octreotide by reverse high performance liquid chromatography

    International Nuclear Information System (INIS)

    Cheng, Z.; Lin, Q.F.; Jin, X.H.; Wang, F.; Bai, H.S.; Chen, D.M.; Fan, H.Q.; Du, J.

    1998-01-01

    DTPA-Octreotide(Pentetreotide), a somatostatin analogue which can bind specifically and with high affinity to somatostatin receptor in vitro and vivo, labeled with 99m Tc by tin reduction in acetate buffer, has been characterized by Reverse-phase High performance Liquid Chromatography. The effect of different solvents, mobile phase pH, linear gradient and the injected volume on the separation efficiency was evaluated. The results show that the separation efficiency is best using μBondapak-C 18 (300x3.9 mm 2 ), linear gradient of 40% to 80% methanol (1.0 ml/min) in 0.05M acetate buffer (pH 5.5) over a 30 min period and maintaining for another 10 min. The labeled product is a mixture which mainly consists of five components (a, b, c, d, e) successfully proved by HPLC. Paper chromatography is also evaluated in this paper. It may be used to determine the radiochemical purity of the labeling product, but is not a good choice for the verification each components. (author)

  18. Triacylglycerol profiling of microalgae strains for biofuel feedstock by liquid chromatography-high-resolution mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    MacDougall, Karen M.; McNichol, Jesse; McGinn, Patrick J.; O' Leary, Stephen J.B.; Melanson, Jeremy E. [Institute for Marine Biosciences, National Research Council of Canada, Halifax, NS (Canada)

    2011-11-15

    Biofuels from photosynthetic microalgae are quickly gaining interest as a viable carbon-neutral energy source. Typically, characterization of algal feedstock involves breaking down triacylglycerols (TAG) and other intact lipids, followed by derivatization of the fatty acids to fatty acid methyl esters prior to analysis by gas chromatography (GC). However, knowledge of the intact lipid profile could offer significant advantages for discovery stage biofuel research such as the selection of an algal strain or the optimization of growth and extraction conditions. Herein, lipid extracts from microalgae were directly analyzed by ultra-high pressure liquid chromatography-mass spectrometry (UHPLC-MS) using a benchtop Orbitrap mass spectrometer. Phospholipids, glycolipids, and TAGs were analyzed in the same chromatographic run, using a combination of accurate mass and diagnostic fragment ions for identification. Using this approach, greater than 100 unique TAGs were identified over the six algal strains studied and TAG profiles were obtained to assess their potential for biofuel applications. Under the growth conditions employed, Botryococcus braunii and Scenedesmus obliquus yielded the most comprehensive TAG profile with a high abundance of TAGs containing oleic acid. (orig.)

  19. Organic monolith frits encased in polyether ether ketone tubing with improved durability for liquid chromatography.

    Science.gov (United States)

    Park, Sin Young; Cheong, Won Jo

    2015-09-01

    This study introduces a preparation method for polymer-encased monolith frits with improved durability for liquid chromatography columns. The inner surface of the polyether ether ketone tubing is pretreated with sulfuric acid in the presence of catalysts (vanadium oxide and sodium sulfate). The tubing was rinsed with water and acetone, flushed with nitrogen, and treated with glycidyl methacrylate. After washing, the monolith reaction mixture composed of lauryl methacrylate, ethylene glycol dimethacrylate, initiator, and porogenic solvent was filled in the tubing and subjected to in situ polymerization. The tubing was cut into thin slices and used as frits for microcolumns. To check their durability, the frit slices were placed in a vial and a heavy impact was applied on the vial by a vortex mixer for various periods. The frits made in the presence of catalysts were found to be more durable than those made without catalysts. Furthermore, when the monolith-incorporated tubing was used as a chromatography column, the column prepared in the presence of catalysts resulted in a better separation efficiency. The separation performance of the columns installed with the polyether ether ketone encased monolith frits was comparable to that of the columns installed with the commercial stainless-steel screen frits. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Evaluation of hydrophilic interaction liquid chromatography stationary phases for analysis of opium alkaloids.

    Science.gov (United States)

    Bagheri, Mohsen; Taheri, Mohammadreza; Farhadpour, Mohsen; Rezadoost, Hassan; Ghassempour, Alireza; Aboul-Enein, Hassan Y

    2017-08-18

    The separation of a mixture containing five major opium alkaloids, namely morphine, codeine, thebaine, noscapine and papaverine has been investigated in hydrophilic interaction liquid chromatography (HILIC) mode using five different stationary phases: bare silica, zwitterion, aminopropyl, diol and cyanopropyl. In order to propose the appropriate column for separation and purification, retention behaviors of the five natural opioids have been studied on mentioned HILIC stationary phases. The mechanism of separation in diverse HILIC media, based on the formation of water-rich layer on surface of the HILIC stationary phases and the physicochemical properties of opium alkaloids, such as pKa (acidic pK) and the octanol-water distribution coefficient (log Do/w) are discussed. Chromatographic responses including modified limit of detection LOD m , signal to noise ratio (S/N) m , and defined modified R Sm have considered for suggestion of the suitable column for quantitative/qualitative and preparative purposes. According to the obtained results, diol stationary phase is best suited for analytical chromatography, whereas bare silica and zwitterionic stationary phases are appropriate for preparative applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Determination of boron in nuclear materials at subppm levels by high pressure liquid chromatography (HPLC)

    International Nuclear Information System (INIS)

    Rao, Radhika M.; Aggarwal, S.K.

    2002-11-01

    Experiments were conducted for the determination of boron in U 3 O 8 powder, aluminium metal and milliQ water using dynamically modified Reversed Phase High Pressure Liquid Chromatography (RP-HPLC) and using two precolumn chromogenic agents viz. chromotropic acid and curcumin for complexing boron. The complex was separated from the excess of reagent and determined by HPLC. When present in subppm levels, chromotropic acid was used successfully only for determination boron in water samples. For determination of boron at subppm levels in uranium and aluminium samples, curcumin was used as the precolumn chromogenic agent. The boron curcumin complex (rosocyanin) was formed after extraction of boron with 2-ethyl-l, 3-hexane diol (EHD). The rosocyanin complex was then separated from excess curcumin by displacement chromatography. Linear calibration curves for boron amounts in the range of 0.02 μg to 0.5 μg were developed with correlation coefficients varying from 0.997 to 0.999 and were used for the determination of boron in aluminium and uranium samples. Precision of about 10% was achieved in samples containing less than 1 ppmw of boron. Detection limit of this method is 0.01 μg boron. (author)

  2. Application of hight performance liquid chromatography with spectrofluorimetric detection for determination of human milk retinol

    Directory of Open Access Journals (Sweden)

    Falahat Pisheh HR

    2001-11-01

    Full Text Available World health organization has introduced concentration of vitamin A in breast milk as a proper indicator for characterization of vitamin A deficiency in lactating mothers and their infants (<6 mo. A normal phase high performance liquid chromatography with spectrofluorometric detection as a specific and sensitive detector was used for characterization of all-trans retional from 13-Cis retinal. The method was sensitive (0.009 ppm and accurate (1±0.054 µ mol/l and had a good recovery percentage (99.36%. This method was more better than before methods and was compatible with the other useful methods. Effect of freezing and defreezing on all-trans retinol content of milk sample was investigated. The result was interesting, whatever all-trans retinol content was bigger, it’s destroying was bigger too. Because of that reseon, day today reproducibility wasn’t good. Standard of retinol was 95% all-trans and pure so we should use this method because two retinol isomers wasn’t separated from each other by reversed phase chromatography and UV detection.

  3. Chemistry and liquid chromatography methods for the analyses of primary oxidation products of triacylglycerols.

    Science.gov (United States)

    Zeb, A

    2015-05-01

    Triacylglycerols (TAGs) are one of the major components of the cells in higher biological systems, which can act as an energy reservoir in the living cells. The unsaturated fatty acid moiety is the key site of oxidation and formation of oxidation compounds. The TAG free radical generates several primary oxidation compounds. These include hydroperoxides, hydroxides, epidioxides, hydroperoxy epidioxides, hydroxyl epidioxides, and epoxides. The presence of these oxidized TAGs in the cell increases the chances of several detrimental processes. For this purpose, several liquid chromatography (LC) methods were reported in their analyses. This review is therefore focused on the chemistry, oxidation, extraction, and the LC methods reported in the analyses of oxidized TAGs. The studies on thin-layer chromatography were mostly focused on the total oxidized TAGs separation and employ hexane as major solvent. High-performance LC (HPLC) methods were discussed in details along with their merits and demerits. It was found that most of the HPLC methods employed isocratic elution with methanol and acetonitrile as major solvents with an ultraviolet detector. The coupling of HPLC with mass spectrometry (MS) highly increases the efficiency of analysis as well as enables reliable structural elucidation. The use of MS was found to be helpful in studying the oxidation chemistry of TAGs and needs to be extended to the complex biological systems.

  4. Insights in groundwater organic matter from Liquid Chromatography-Organic Carbon Detection

    Science.gov (United States)

    Rutlidge, H.; Oudone, P.; McDonough, L.; Andersen, M. S.; Baker, A.; Meredith, K.; O'Carroll, D. M.

    2017-12-01

    Understanding the processes that control the concentration and characteristics of organic matter in groundwater has important implications for the terrestrial global carbon budget. Liquid Chromatography - Organic Carbon Detection (LC-OCD) is a size-exclusion based chromatography technique that separates the organic carbon into molecular weight size fractions of biopolymers, humic substances, building blocks (degradation products of humic substances), low molecular weight acids and low molecular weight neutrals. Groundwater and surface water samples were collected from a range of locations in Australia representing different surface soil, land cover, recharge type and hydrological properties. At one site hyporheic zone samples were also collected from beneath a stream. The results showed a general decrease in the aromaticity and molecular weight indices going from surface water, hyporheic downwelling and groundwater samples. The aquifer substrate also affected the organic composition. For example, groundwater samples collected from a zone of fractured rock showed a relative decrease in the proportion of humic substances, suggestive of sorption or degradation of humic substances. This work demonstrates the potential for using LC-OCD in elucidating the processes that control the concentration and characteristics of organic matter in groundwater.

  5. Multi-detection of corticosteroids in sports doping and veterinary control using high-resolution liquid chromatography/time-of-flight mass spectrometry

    NARCIS (Netherlands)

    Touber, M.E.; Engelen, M.C.; Georgakopoulus, C.; Rhijn, van J.A.; Nielen, M.W.F.

    2007-01-01

    A liquid chromatography/time-of-flight mass spectrometry (LC/TOFMS) method was developed using the latest high-resolution LC column technology, the ultra performance liquid chromatography (UPLC (TM)), and electrospray ionization (ESI) in the positive ion mode. Gradient UPLC separation conditions

  6. Quantification of liquid products from the electroreduction of CO2 and CO using static headspace-gas chromatography and nuclear magnetic resonance spectroscopy

    DEFF Research Database (Denmark)

    Bertheussen, Erlend; Abghoui, Younes; Jovanov, Zarko P.

    2017-01-01

    Static headspace-gas chromatography (HS-GC) useful for ex-situ liquid product analysis. Could complement high-performance liquid chromatography and NMR spectroscopy. Particularly high sensitivity towards compounds with high vapor pressure. Detection limits below 0.5μM were shown for acetaldehyde...

  7. Purification of human albumin by the combination of the method of Cohn with liquid chromatography

    Directory of Open Access Journals (Sweden)

    Tanaka K.

    1998-01-01

    Full Text Available Large volumes of plasma can be fractionated by the method of Cohn at low cost. However, liquid chromatography is superior in terms of the quality of the product obtained. In order to combine the advantages of each method, we developed an integrated method for the production of human albumin and immunoglobulin G (IgG. The cryoprecipitate was first removed from plasma for the production of factor VIII and the supernatant of the cryoprecipitate was fractionated by the method of Cohn. The first precipitate, containing fractions (F-I + II + III, was used for the production of IgG by the chromatographic method (see Tanaka K et al. (1998 Brazilian Journal of Medical and Biological Research, 31: 1375-1381. The supernatant of F-I + II + III was submitted to a second precipitation and F-IV was obtained and discarded. Albumin was obtained from the supernatant of the precipitate F-IV by liquid chromatography, ion-exchange on DEAE-Sepharose FF, filtration through Sephacryl S-200 HR and introduction of heat treatment for fatty acid precipitation. Viral inactivation was performed by pasteurization at 60ºC for 10 h. The albumin product obtained by the proposed procedure was more than 99% pure for the 15 lots of albumin produced, with a mean yield of 25.0 ± 0.5 g/l plasma, containing 99.0 to 99.3% monomer, 0.7 to 1.0% dimers, and no polymers. Prekallikrein activator levels were <=5 IU/ml. This product satisfies the requirements of the 1997 Pharmacopée Européenne.

  8. Integration of Electrochemistry with Ultra Performance Liquid Chromatography/Mass Spectrometry (UPLC/MS)

    Science.gov (United States)

    Cai, Yi; Zheng, Qiuling; Liu, Yong; Helmy, Roy; Loo, Joseph A.; Chen, Hao

    2015-01-01

    This study presents the development of ultra-performance liquid chromatography/mass spectrometry (UPLC/MS) combined with electrochemistry (EC) for the first time and its application for the structural analysis of disulfide bond-containing proteins/peptides. In our approach, a protein/peptide mixture sample undergoes fast UPLC separation and subsequent electrochemical reduction in an electrochemical flow cell followed by online MS and MS/MS analyses. The electrochemical cell is coupled to MS using our recently developed desorption electrospray ionization (DESI) interface. Using this UPLC/EC/DESI-MS method, disulfide bond-containing peptides can be differentiated from those without disulfide bonds as the former are electroactive and reducible. Tandem MS analysis of the disulfide-reduced peptide ions provides increased sequence and disulfide linkage pattern information. In a reactive DESI-MS detection experiment in which a supercharging reagent was used to dope the DESI spray solvent, increased charging was obtained for the UPLC-separated proteins. Strikingly, upon online electrolytic reduction, supercharged proteins (e.g., α-lactalbumin) showed even higher charging, which would be useful in top-down protein structure analysis as increased charges are known to promote protein ion dissociation. Also, the separation speed and sensitivity are enhanced by approximately 1~2 orders of magnitude by using UPLC for the LC/EC/MS platform, in comparison to the previously used high performance liquid chromatography (HPLC). This UPLC/EC/DESI-MS method combines the power of fast UPLC separation, fast electrochemical conversion and online MS structural analysis for a potentially valuable tool for proteomics research and bioanalysis. PMID:26307715

  9. Identification and Quantification of the Major Constituents in Egyptian Carob Extract by Liquid Chromatography?Electrospray Ionization-Tandem Mass Spectrometry

    OpenAIRE

    Owis, Asmaa Ibrahim; El-Naggar, El-Motaz Bellah

    2016-01-01

    Background: Carob - Ceratonia siliqua L., commonly known as St John's-bread or locust bean, family Fabaceae - is one of the most useful native Mediterranean trees. There is no data about the chromatography methods performed by high performance liquid chromatography (HPLC) for determining polyphenols in Egyptian carob pods. Objective: To establish a sensitive and specific liquid chromatography?electrospray ionization (ESI)-tandem mass spectrometry (MSn) methodology for the identification of th...

  10. Comparative urine analysis by liquid chromatography-mass spectrometry and multivariate statistics : Method development, evaluation, and application to proteinuria

    NARCIS (Netherlands)

    Kemperman, Ramses F. J.; Horvatovich, Peter L.; Hoekman, Berend; Reijmers, Theo H.; Muskiet, Frits A. J.; Bischoff, Rainer

    2007-01-01

    We describe a platform for the comparative profiling of urine using reversed-phase liquid chromatography-mass spectrometry (LC-MS) and multivariate statistical data analysis. Urinary compounds were separated by gradient elution and subsequently detected by electrospray Ion-Trap MS. The lower limit

  11. High-Pressure Liquid Chromatography of Irradiated Nuclear Fue - Separation of Neodymium for Burn-up Determination

    DEFF Research Database (Denmark)

    Larsen, N. R.

    1979-01-01

    Neodymium is separated from solutions of spent nuclear fuel by high-pressure liquid chromatography in methanol-nitric acid-water media using an anion-exchange column. Chromatograms obtained by monitoring at 280 nm, illustrate the difficulties especially with the fission product ruthenium in nuclear...

  12. Monolithic columns based on a poly(styrene-divinylbenzene-methacrylic acid) copolymer for capillary liquid chromatography of small organic molecules

    Czech Academy of Sciences Publication Activity Database

    Svobodová, A.; Křížek, T.; Širc, Jakub; Šálek, Petr; Tesařová, E.; Coufal, P.; Štulík, K.

    2011-01-01

    Roč. 1218, č. 11 (2011), s. 1544-1547 ISSN 0021-9673 R&D Projects: GA AV ČR KAN200520804 Institutional research plan: CEZ:AV0Z40500505 Keywords : capillary liquid chromatography * methacrylic acid * polystyrene-based monolithic stationary phase Subject RIV: EI - Biotechnology ; Bionics Impact factor: 4.531, year: 2011

  13. Novel method for measurement of glutathione kinetics in neonates using liquid chromatography coupled to isotope ratio mass spectrometry

    NARCIS (Netherlands)

    Schierbeek, Henk; te Braake, Frans; Godin, Jean-Philippe; Fay, Laurent-Bernard; van Goudoever, Johannes B.

    2007-01-01

    A novel analytical method using liquid chromatography coupled to isotope ratio mass spectrometry (LC/IRMS) was developed for measuring the fractional synthesis rate (FSR) of glutathione (GSH) in neonates after infusion of [1-(13)C]-glycine as a tracer. After transformation of GSH into GSSG, its

  14. Confirmation of synthetic glucocorticoids with liquid chromatography/mass spectrometry: Organization and results of an international interlaboratory comparison test

    NARCIS (Netherlands)

    Hauwe, O. van den; Campbell, K.; Crooks, S.R.H.; Schilt, R.; Peteghem, C.H. van

    2005-01-01

    Within the framework of a European Union (EU) research project entitled "Food Safety Screening: Synthetic Glucocorticoids (QLK1-1999-00122)," an international interlaboratory ring test was organized to compare and evaluate different liquid chromatography/mass spectrometry (LC/MS) confirmatory

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

    NARCIS (Netherlands)

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

    2009-01-01

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

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

    NARCIS (Netherlands)

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

    2009-01-01

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

  17. Elucidation and identification of amino acid containing membrane lipids using liquid chromatography/high-resolution mass spectrometry

    NARCIS (Netherlands)

    Moore, E.K.; Hopmans, E.C.; Rijpstra, W.I.C.; Villanueva, L.; Sinninghe Damsté, J.S.

    2016-01-01

    RATIONALE: Intact polar lipids (IPLs) are the building blocks of cell membranes, and amino acid containing IPLs havebeen observed to be involved in response to changing environmental conditions in various species of bacteri a. High-performance liquid chromatography/mass spectrometry (HPLC/MS) has

  18. Simultaneous determination of estrogens and progestogens in honey using high performance liquid chromatography-tandem mass spectrometry

    Science.gov (United States)

    This work describes the development and validation of a method for the simultaneous determination of 13 estrogens and progestogens in honey by high performance liquid chromatography-tandem mass spectrometry. The target compounds were preconcentrated by solid phase extraction. Pretreatment variables ...

  19. Simple, rapid, and sensitive liquid chromatography-fluorescence method for the quantification of tranexamic acid in blood

    NARCIS (Netherlands)

    Huertas-Pérez, José Fernando; Heger, Michal; Dekker, Henk; Krabbe, Hans; Lankelma, Jan; Ariese, Freek

    2007-01-01

    Tranexamic acid (TA) is a synthetic antifibrinolytic agent that is being considered as a candidate adjuvant drug for site-specific pharmaco-laser therapy of port wine stains. For drug utility studies, a high-performance liquid chromatography (HPLC)-fluorescence method was developed for the

  20. Analysis of aqueous humour in uveitis by high performance liquid chromatography and sodium dodecyl sulphate-polyacrylamide gel electrophoresis

    NARCIS (Netherlands)

    Murray, P. I.; Hoekzema, R.; Luyendijk, L.; Kijlstra, A.

    1992-01-01

    Aqueous humour from patients with Fuchs' heterochromic cyclitis (FHC) and other types of uveitis was analysed by high performance liquid chromatography (HPLC) and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Using HPLC, the number of peaks and their respective elution times